Are there issues you can create using coin control with watch only wallet on a single public address?
I just wondered why electrum does not default to using a single uxto input for a spend in this case.
Thanks for everyones information. Very helpful.
The electrum coin selection algorithm which prioritizes all selection of UTXOs on that address is base on their own method of privacy control. As they think a single utxo from that address exposes one privacy. This is just their own way of privacy control which definitely doesn’t goes for most users that’s why there is the coin control protocol.
Here is the quote to their statement on GitHub
Attempts to better preserve user privacy.
First, if any coin is spent from a user address, all coins are.
Compared to spending from other addresses to make up an amount, this reduces
information leakage about sender holdings. It also helps to
reduce blockchain UTXO bloat, and reduce future privacy loss that
would come from reusing that address' remaining UTXOs.
Second, it penalizes change that is quite different to the sent amount.
Third, it penalizes change that is too big.
As for the coin control protocol I think you need to mark this coins every time you need to make use of them in a transaction after closing the electrum app. If you wish to permanently ban a utxo the thing to use is the freeze coin option instead.