Agree. Credential syncing is important. Use case: I create an account using using a Yubikey on my desktop, then want to access that account from my mobile phon

Agree. Credential syncing is important. Use case: I create an account using using a Yubikey on my desktop, then want to access that account from my mobile phone using a fingerprint. How does the website know I'm the same person? Keybase has a nifty personal web-of-trust for this stuff, but (A) that ties you to a single strong identity and (B) you can't really use that identity outside of their services.