Why not?
I've seen plenty of gas motors with that black oily sludge inside intake plenums,runners and on valves. As the engine acumulates miles, the blowby/oily crankcase fumes get worse and lead to more deposits. Diesels have more hardware that gets destroyed by the deposits. Gassers get intake and valve deposits. After shutdown, the fumes condense on the back sides of throttle bodies and IAC pintles, also.

http://www.airnowsupply.com/filter-type ... lters.html

These filter/separators are made to thwart "planned obsolecence" by helping you get double or triple the life out of your engine.

Same for the Bypass oil filtration systems and low micron fuel filtering.

If all you are looking for is a Crank Case Vent Catch Can? Than look no further than getting a PROVENT. Mainly used on Diesels due to more CCV pressure but can be used on any engine. I have installed them on several.

I know it'd be more beneficial if it was a turbo application, but there is no need for that crappy oil you see in a catch can to be allowed back into the intake. There once was a day there was no such thing as a PCV.