[Dylan16807]

The keys are authenticator device specific. So if you put it on your keychain you never need to generate anything to check your email on random computers. If you use a software solution, then you need to sync the vault in some way, and again don't need to generate anything here.

If you're worried about making a brand new passkey because you're logging in from scratch, that means you need some other kind of authentication to start the process. And that's solidly outside the scope of passkeys, so it's hard to say how difficult it would be. (But if you have an alternate login method, a good system wouldn't force you to make a temporary passkey, it would just let you check your email and log out.) (Also it shouldn't take more than a minute to do key creation/deletion in any reasonable implementation.)