I was with you until "doesn't grant them info that they don't already have." It gives them the opportunity to update their face model of you in a confirmed and consistent manner.

It also doesn't improve anything:

An agent comparison of you vs the id is still considered to be the gold standard. When this system fails, you have to default to the agent's comparison. This is a slow down compared to the previous scenario.

The time for an id comparison isn't the bottleneck in security. It's the physical actions used to go through the TSA and the built in inconsistency to prevent people from speedrunning the screening.