I agree. Biometrics are a terrible idea for authentication to a computer system. If you cannot change it, then it shouldn't be used for authentication!
However, biometrics are pretty decent authentication of your real-life identity to a fellow human being that is in your physical presence (barring perhaps identical twins?). If I can't physically see you and touch your face to make sure you aren't wearing a mask, or check your hands to make sure you aren't wearing special gloves, I can't really trust your biometric authentication.
If we are being super paranoid, then I can't even trust your biometric authentication even if we are having a live Skype video chat when technology like this exists and will only get better over time.