Would be actually useful for when you share a car with family members and want it to remember seat position when you are both in car. Strange they haven't done it, but headlines "Tesla facial recognition" would make few people wet their bottoms. Even on this forum.
I’m more of a mind to criticize it based on how often Technology fails.
Tesla has had multiple recall issues with the interface pad malfunctioning or not even turning on.
Meanwhile I can just put a key in my car and go. Sure, someone could steal the key - but statistically that is far less likely that a software or hardware failure.