If a system is able to identify a face with better-than-chance accuracy then it shifts things from "We have absolutely no evidence you were there so we have to believe your alibi." to "We have cause to believe you might have been there so we can doubt your alibi. " That's a long way from proof, but it could be enough to get a judge to issue a search warrant or persuade a jury that other evidence is true.

This is not a good thing. Probability-based evidence such as DNA relies on people understanding probability, and most people really don't. If this system is used in the criminal justice system it will very likely lead to innocent people going to prison.