The "benefits" are larger molecule size (less loss of pressure), drier, less affected by temperature gradients, portable with high pressure tank(for the offroad folks).
I've seen reports of of a few percent in tractor trailer uses, over a fleet of a couple thousand trucks and millions of miles annually, that 2-3 percent could add up quite a bit. Not sure if the cost is justified but it is what it is. In a personal vehicle or tractor, I really don't see any benefit. I was charged for it when I bought my new truck, 30$ surcharge, I was pissed I got charged for it let the salesman know. Like said, compressed air is 70 some percent nitrogen to begin with, if you want dry air put a inline drier in.