I think the point is that anybody that is just joining the system would not really understand how to manage keys.. and you would restrict to tech savvy people if you only allow external signers as an option
Maybe the focus should be on how to restore control of your identity in an easy way in the event your key gets compromised.
Imagine something very simple... I get a key pair when I sign up and I'm asked to also add a passphrase which generates another signature together with my key and that signature is part of my eventkind 0 profile
if in the event a hacker gets control of the key (without passphrase), I'll always be able to create any random new key pair and sign a new event with my old key + passphrase showing that I'm the real owner of the old key that now wants to move to the new key?
Something very simple that does not need bip39 or any other thing... but that most users would understand?
