I see no reason why venting into the atmosphere is problematic. The recurculation is strictly as many have said for emissions purposes only. Look at any earily cummins or any off highway diesel that is not bound by emission regulations, the crankcase vent is a hose off the valve cover venting straight to the ground. I have seen this on cats, John deeres, izuzus, detroits, Perkins amongst others. I run a catch can that has baffels in it, it vents into the atmosphere. I consider this to be a happy medium between environment and engine cleanlyness. It's better for the environment than nothing since I'm catching the majority of the oil in the can and better for the engine since it's not coating the intake and turbo with oil with the bonus of no grey smoke the first time you get on it in the morning.