I'm not sure whether this applies to sudo, but for device access, a biometric like a fingerprint is neither an identifier nor a password. It is closer to a sess

I'm not sure whether this applies to sudo, but for device access, a biometric like a fingerprint is neither an identifier nor a password. It is closer to a session key. In any finger print system I have used, you must login with a username and password, then you have a session of access. The finger print can extend that session for some hours or days. Eventually the session rules require you to login again. Without having a recent session, your fingerprint does not provide access. Yes, like any session-based access, it is a compromise between convenience and security. For frequent usage like phone access, I feel like it is a reasonable compromise.