Maybe I'm not getting it. Doesn't the problem start with ever deleting a passkey? That is: how do you ever know you don't need it anymore? Also, what is the a

Maybe I'm not getting it. Doesn't the problem start with ever deleting a passkey? That is: how do you ever know you don't need it anymore? Also, what is the alternative? Just a password that you store in the vault? Seems like deleting those gets you back to the same place (with all the disadvantage of a plain password).