@iMeddles the problem is not the nature of any of the authentication devices but rather the fact that you're losing the multi in multi-factor authentication.
With multi-factor authentication, if someone steals my security key, they still need to guess my #passwords. If someone cracks my passwords, they still need to get their hands on my key.
With #passkeys, this is no longer true and all your authentication and identity is rolled into one device that if compromised, compromises everything. #MFA