I could understand that at a stand still they become heat vents. There is a whole lotta heat under the hood of our cars.
I agree that they may not be high enough up in the airflow to make a big difference in power, but, how big is big. If they aren't isolated to feed the carb directly, they will actually make no difference at all. A properly sealed fresh air system can remove at least a couple of tenths at the drag strip though. How much of a difference the smallish, low factory scoops make may be pretty minimal.
But it is cool, none the less.