No idea, since the NFC was actually pretty convenient. Considering the Yubico authenticator has a relatively small amount of downloads on the play store (50k), I'm guessing that feature wasn't used that much.
If you're thinking of getting the USB C versions of Yubikeys and using them with your phone, it does work but since the Yubikey appears as a keyboard, it disables the Android keyboard while it's plugged in. If I remember correctly, U2F support on Android also requires installing the Google authenticator app even though you might not store any codes in it.
You'd think it would be easier to have these things working.
Interesting. Didn't realize you could use that with Android. Sounds like the YubiKey 4C may be the best option for me since it looks like I could plug it directly into my phone and laptop.
