I actually prefer using FIDO2 as a second factor only cos I use YubiKey which can only store 100 RKs.

Depending on the security needs using hardware based security as a second factor while still requiring some other form of auth is not actually a bad idea.

Public key cryptography tied to physical hardware, so if you lose your phone / usb key, you need to use your backup recovery code; a fairly short one time password that negates the security benefits of Fido in one easy step.

It can also use biometrics, but that requires every device you log in on to have biometric readers.