We had originally planned to go all-in on passkeys for ONCE/Campfire, and we built the early authentication system entirely around that. It was not a simple setup! Handling passkeys properly is surprisingly complicated on the backend, but we got it done. Unfortunately, the user experience kinda sucked, so we ended up ripping it all out...
It’s not skipping MFA cos some media can provide more than one factor.
E.g. YubiKey 5 (presence of the device) + PIN (knowledge of some credentials) = 2 factors
Or YubiKey Bio (presence of the device) + fingerprint (biological proof of ownership) = 2 factors
And actually unless you use one password manager database for passwords, another one for OTPs, and never unlock them together on the same machine, it’s not MFA but 1FA. Cos if you have them all at one place, you can only provide one factor (knowledge of the manager password, unless you program an FPGA to simulate a write only store or something).