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...
I do think that we need more standard procedures around what a reset/authorize new device looks like in a passkey world. There’s a lot about that process that just seems like it’s up to the implementer. But I don’t think that invalidates passkeys as a whole, and most people are going to have access to their mobile device for 2 factor no matter where they are.