So our defense against terrorists is to make them buy an airplane ticket?
That's not really an additional layer, as it's so easily circumvented. However, there is a shred of better security, just because there are less people in the area near the gate. So, true, the terrorist will have no issue circumventing this layer, but if C"V something were to happen, it would be easier to neutralize the terrorist when there are less people around.
Again, I agree with you that layer is totally meaningless. I'm just trying to understand it from their side.