I think its beneficial even without direct air flow. Air will still move thru it, think how much air is being thrown thru the front of the car at speed. Air will be all over that thing. Plus surface area is still surface area.
Again this would be an option if you were running a tubular crash bar like Deadhook or DaVinci, But I would NOT run this with a stock crash bar. Not all surface area is created equal. You can have too much of a good thing. The whole point of having an intercooler IS to have direct airflow. that is the whole point of the design. It doesn't matter how much air is being thrown around it if half of it is sandwiched behind a brick-wall and a hot radiator. If you fill in the 1.5 inches of space between the crash bar and radiator there IS NOT enough, if any, air flow to go through the fins of the IC to be effective at reducing charge air temp.
I am just saying, that without airflow through the fins, the air in the upper portion, yes, will move through internally, but it will not cool down and possibly heat up because of the lack of airflow. Our cars already have a dinky radiator and can overheat if pushed in stock form and reducing any more airflow to it will only cause more issues.
IMO, you are adding unnecessary weight and problems IF you use the stock crash bar and this intercooler.