I live next to the ocean, and often, when I'm working at the marina, my truck gets covered with salt spray. Corrosion in general, will be a bigger trouble than the air cleaner letting salt into the engine!
Back when I was into LandRovers, it was always said that oil baths would filter out more, and finer junk. I've never read anything that proves this, however, one way or the other.
Having used both the oil bath, and a paper element on my truck, the oil bath is quieter. With a paper element, I can hear more "sucking" from the carb.
