Comment by MetroWind

> The passkeys most people use are synced passkeys, stored in iCloud Keychain, Google Password Manager, 1Password, Bitwarden or whatever other software of your choosing

Sorry but this is the whole problem with passkey: you are forced to rely on a 3rd party to take care of your credientials, on their computers, with their software. This is like a text book example of a trap: someone set up something that looks harmless/invisible, you walk into it, and that someone now has some leverage over you.