* Easy to understand. (A password is just a word/phrase/string of characters only you know.)
* Easy to use. (Using a password only requires remembering and typing it in when prompted.)
* Convenient. (Only your ability to remember and type required. No other tools or gadgets required.)
* Simple. (All of the above.)
If something needs an essay to describe itself, it's not killing off passwords.
Do you really want your only means of logging into a service identify you because it's also the only way you log into your banking?
And should you want to kill off an identity so you want to have to register everything?!
Passwords should be easy to retire and change if they are compromised. You can' easily change your fingerprint or iris circle on demand, if somebody makes a good enough copy.
On the other hand, I don't really know how would that work on desktops, should chrome use a Windows service for that? Would it use its own servers? Apple would probably do it themselves. And how about Linux? Would a cross platform option ever exist? Maybe 1password?
* Easy to understand. Your device will just ask "sign in?"
* Easy to use. Your device will just ask "sign in?"
* Convenient. Nothing to remember, nothing to do
* Simple (all of the above)
Passkeys are/will-be way simpler than passwords for the majority of users