Hello, thanks for highliting this implementation. Sorry that the jury didn’t not understood better the fact that it provides the highest security level you can have with a device we all already have in our pocket.
The point with secp256r1 is to benefit from smartphone secure enclave, giving access to the best security you can have with a smartphone. The day Ed25519 is implemented, it will be superior (might happen from 6 month to several years). I doubt secp256k1 will ever be.
This is not the subject here, but Yubikey are not more UX friendly than a hardware wallet. From my biased perspective (i have conflict of interest in the next sentence), if you are to buy a device, buy a Ledger. Fido is implemented as a secondary feature (https://support.ledger.com/hc/en-us/articles/115005198545-FIDO-U2F?docs=true), and its core function is cryptocurrencies handling.