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...
That was my take too.
Security training was something you know, and something you have.
You know your password, and you have a device that can receive another way to authorize. So you can lose one and not be compromised.
Passkeys just skip that “something you have”. So you lose your password manager, and they have both?