To date, the core of our firmware is also used by NitroKey [1], Signet HC [2] and OnlyKey [3]. We did a pretty significant refactor [4] to make the lib even easier to use as part of our MOSS award [5].
Hopefully we'll see even more products -and thus user adoption- of fido2/webauthn.
If anyone is reading, has a hardware project and would like to add fido2 functionality, please reach out!