The idea is that you aren't giving away any kind of biometric data, just using your fingerprint/face-unlock/etc to "unlock" the key used for signing the request locally.
It could also be implemented in a way where it's behind a password instead of biometrics. Yubikey and the likes already use this method.
It could also be implemented in a way where it's behind a password instead of biometrics. Yubikey and the likes already use this method.