Actually, the labor is worse than pointless. The travel productivity cost to society is astronomical. Like, literally everyone would be better off if the TSA paid people to just stay home and do absolutely nothing at all. The current employees would have their time back, the travelers would have their time back, and travel security would be no worse in any statistically meaningful sense. But the US has a huge contingent of people fundamentally opposed to doing things like this even when it would make literally everything better for literally everyone.
So here we are.