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...
Import export is not the same as interoperability
The interoperability already exists in the protocol webauthn, part of FIDO2 which has been around for almost a decade. Interoperability is not remotely an issue with passkeys. Imported/export is/was and also already has a solution in the works.
So I can use the same passkey from say, bitwarden and windows hello? Why do you even need import export then?
Yes you can use a passkey set up on any given service to authenticate to a service that supports passkeys. You’d need import/export to move a given passkey from bitwarden to Windows.