No they don't. They behave like a username/password combination. A username is an individual identifier and a password is a confirmation that the identifier is

No they don't. They behave like a username/password combination. A username is an individual identifier and a password is a confirmation that the identifier is valid for the person it's identifying. TouchID and FaceID confirm both - that it's the correct user that has access and that the user is who they say they are.