Should Coin Control be a default feature?

Coin Control is honestly one of the top features in Bitcoin Core for me, and it's a big reason why I prefer this wallet over others. Aside from the fact that it’s super well-reviewed and reliable, it’s kinda strange that Coin Control is buried in the menu and has to be turned on manually. I really think if it was default, more folks would pay attention to their privacy while sending coins since they’d have to pick the UTXOs to use each time. Personally, learning about Coin Control was a big deal for me it helped me grasp how transactions work and made me realize the risks of just hitting ‘send’ and letting the software choose UTXOs without thinking. Given that Bitcoin Core is meant to be advanced, it seems like this should be standard. Just my two cents.

It's hidden because it's an advanced feature and bad coin selection can actually hurt you in the long run on fees and with some other traps (e.g. making dusty outputs, etc.) If you need privacy where some UTXOs cannot be spent with others, make a separate wallet.

Just as said above this features are advanced features that might look much better to you but in some cases some users will most preferably not want it because to them it will create extra stress of having to select UTXO before sending while they prefer the wallet sort that out itself, I can remember this was similar to when wallets started making transactions RBFed on default which upon its importance didn’t sit well with some people because they wanted non RBF transactions, so advanced settings like should stay the way they are

People are already complaining about bitcoin being complex when they use it, enabling advanced features by default will add to that complexity for them (even if it doesn't look complex to some of us) and it will degrade their experience even more.

In my opinion, coin control is the straightforward feature and it really should be enabled by default. Hiding it away in the advanced menu is something like putting compartments inside the jitney bag and then making them invisible. My favorite wallet which is Sparrow handles this well by having a dedicated visible by default UTXO section in the interface making coin control easily accessible and user-friendly. That said, people have different preferences, and not everyone will see it the same way.I use Bitcoin Core solely as a node, not for its wallet functionality.

Well, there are many features, which are hidden by default, and can show you, how things are designed under the hood. For example: should sighashes be visible by default? Should you be able to pick in GUI, that you want to sign the first input with SIGHASH_ALL, the second input with SIGHASH_SINGLE, the first signature in the third input with SIGHASH_SINGLE | SIGHASH_ANYONECANPAY, and the second signature in the third input with SIGHASH_NONE? Should you get a list of all signatures in a given transaction, with their z-values, and see exactly, what and where is signed? For developers, it may be useful to see more details. But for regular users, it can make things more complex. In practice, Bitcoin Core is used not only to handle Bitcoin. It is copy-pasted into a lot of altcoins, which also means, that in some cases, when some project is at some early stage, then users are basically forced to use "Altcoin Core", because it is the only working client for a given altcoin. So, surprisingly, changes in Bitcoin Core can affect altcoin users first, if most Bitcoin users are not running full nodes, and use alternative clients.

Yeah I guess you could just use a separate wallet for non-KYC coins and have another wallet for KYC'd coins. But back then Bitcoin Core did not have multi wallet support. I have no updated yet (im still using an old version) but I think the new Bitcoin Core versions have a way to quickly load wallets. In the older versions it always saved wallets as wallet.dat. Can you create a new wallet without having to delete the wallet.dat file? I guess it also asks you for a name for the wallet? Also in the older versions you needed to change the name of your wallet.dat to wallet2.dat or something, and close the program and open it again so it again and have the wallet you wanted to load named wallet.dat, it was really annoying hence why I just have one single wallet for all transactions, which is now a problem if I want to get it audited to buy real estate or whatever since it's all within the same wallet. I guess I could have audit for specific addresses but I haven't looked into how this works yet.

Yes Multiwallet support has significantly improved since it was introduced almost a decade ago.

Well, in my opinion that is overkill compared to Coin Control. I think anyone should be able to understand the concept of, you are want to move this, this, and this coin into another address or various addresses in the transaction, and so with the GUI this becomes easier. I just don't see when I would make a transaction without ever using CoinJoin. I guess I should have started from scratch with a non-KYC and KYC wallet but back then I didn't even have a notion of that. I have heard various people now mention Sparrow, it must be pretty good, but I don't want to have to now look into another software, who is coding it etc. With Bitcoin Core, you get probably the most peer reviewed software in the world. Everyone is trying to screw up Bitcoin's network, so im sure every day the code is being inspected by both proponents that want to protect their money, and hackers that want to hack the network, so the result is, a pretty monitored software that guarantees when someone adds something they know a lot of people are watching. I just don't see myself access my keys with anything but Bitcoin Core as it stands. I just wish they cared a bit more about wallet users and added some ease of life features which wouldn't clutter the code since it would be pretty straightforward stuff, some improvements on GUI etc.

I completely agree with this. Wasabi has three different coin selection modes but they are hidden by default because the automatic coin selector does a much better selection than most users do. That's possible because the wallet knows who knows about each of your UTXOs and then it can select automatically UTXOs that are already known by the payee or, if that's not possible, it allows you to decide who can know about the payment transaction. Wasabi also tries to avoid creating change as Bitcoin Core does and suggests different amounts close enough to the attempted payment to avoid it. However, there are cases where you know exactly what you want, like spending one very specific UTXO as a whole (1-in, 1-out) or a set of specified coins as a whole. In those cases, the user should be able to select the coins themselves. Wasabi allows you to do that too but it displays who is going to be able to track that transaction and alerts you in case you are mixing private coins together with non-private coins. Finally, there are other cases where the user thinks they can do better than the software and wants to see for themselves the set of coins it will use and change it. This scenario is not absurd; in fact, users feel more internal peace/safety if they select the coins. Wasabi, for example, allows users to select the coins but the software will inform you if your selection can be improved, if it ruins your wallet's privacy, who will be able to track you, and whether change can be avoided or not. I was against manual coin selection for a long, long time until I realized that having no control over the coin selection, even if the wallet could do it a million times better than you, creates a disgusting feeling of uncertainty and fear. Summarizing: Automatic coin selection should be by default. Assisted manual coin selection should be there but hidden. Unassisted manual coin selection should be available too but really hidden.

Yeah, you can screw up real bad when it comes to privacy. Even if you are separating non-KYC with KYC wallets, you may just not want to tie 2 different addresses that are both non-KYC or KYC. So you are going to need coin control enabled, because I don't think anyone wants to have a separate wallet for each separate sub criteria after the main non-KYC/KYC criterion so you are better off just controlling your utxos manually before any transactions. Just click on the different utxos checkboxes until the amount fills the needed amount of BTCyou want to sell and you are set, anything above that just goes into a new address as change as usual.

In my experience users screw up their privacy precisely because manual coin control and that's why IMO manual coin control should be hidden by default. Separating non-KYC from KYC wallets is a sad solution. It means that your wallet does a poor job managing the knowledge about how hows what and how to minimize it. If your wallet doesn't allow you manage manage that then you will screw it up sooner or later. This is in most of the cases a very bad idea. It is very unlike that users know exactly all people or entities that can track each of their utxos.

No, it isn't a straightforward feature. You can read what pooya87 said above; To you, it might be a straightforward feature, but to an average bob, it is not. If the coin control function ends in setting the transaction fee by oneself, I would have agreed that it is a straightforward something. But selecting the utxo you want to spend from makes a bit technical. Anyone who feels the need for coin control should not find it difficult enabling it.

How can I get btc from "change invisible" address ? I have old bitcoin core wallet, the GUI I see one btc, but if I check the address via blockchain, I see another btc

I confess I don't use coin_control very often, I rarely use it in Bitcoin Core, which already offers a satisfactory coin selection, in my opinion. Moreover, Bitcoin Core's enabled Coin Control interface is extremely crude and ugly. Once enabled, there should only be a single button on the send tab for any user to use, similar to how some wallets implement this. The enabled coin_control interface takes up a lot of unnecessary space on the send tab, everything could be replaced with a single button or something similar that doesn't clutter the UI unnecessarily. Fun fact: It is possible to enable the coin control feature, select the coins you want to spend/freeze and then disable the coin control, the coins will remain selected even with the disabled feature.

Don’t mind my asking OP as you only just mentioned it, explained aspects to it but, no definition to it and I don’t really understand it though, it seems to be this important so, What then is coin control? I could have taken it for its literal meaning but, wouldn’t want to take it out of context as per application. I was doing my reading through and though I was following up on a couple of comments as they stayed close to the basics as possible, I wasn’t catching what was meant by UTXO and had to search it on the web and this is what I found out: The way I understand this though is that, it translate to mean balance. In essence, if someone is sending a transaction on the Bitcoin network, let’s say you had 0.5 BTC in your wallet and you wanted to transact just 0.2 BTC, the network ends up sending the entire 0.5 BTC and returns 0.3 BTC back to you. Like it does cash and balancing at the same time hence, it’s not a single pathway but double or 2 transactions. Did I get that right?

After doing some research, here’s what I understand. Sometimes, when you use Bitcoin Core, it creates a change address.This is where the extra BTC from a transaction goes. So, even if your main address shows one amount, another part of your wallet (the change address) might hold more BTC. That’s why the total in your wallet can be different from what shows on the blockchain when you check just one address. But don’t worry, if it’s the same wallet, all that BTC is still yours.

In Bitcoin when you spend one or more UTXOs, they are spent and destroyed in total and any excess coins need to be returned as change back into your own wallet. Bitcoin is not account-based as Ethereum, it's UTXO-based. Coin control means that the user chooses which UTXOs are to be spent as inputs of a transaction outgoing from user's wallet. The country where I live e.g. allows me to spend coins tax-free when I hodled those coins for more than a year. So, if I want to make sure that I spend only tax-free UTXOs for me, I'd use coin control and choose only old enough UTXOs as inputs for tax-free spending.