Welcome to the Team Andre!
Air rides are normally selected so that the car can be parked on the ground at a car show to impress ... ?????? The people they are trying to impress I haven't met yet, but people who invest in air rides go to a lot of expense to impress them.
An air ride suspension doesn't necessitate a rough ride as many luxury yachts rely on air bags for their suspension (old Caddys and new Lincolns do as well as Pugeot and a Swedish car whos name escapes me but it isn't a Volvo). I have a few people on this board who claim that it is also used as a performance suspension, but I haven't found a car that competes under any sanctioning rules for drag racing, road racing, Formula one racing CanAm or TransAm or NASCAR racing, but that doesn't mean there isn't a competitive car out there some where.
A lot of your rough riding could well be the fault of the 18 and 20 inch wheels if the side wall profile eliminates the possibility of the side wall flexing to soften some of the bumps. I have twenty inch wheels on my Silverado pick-up truck with LT tires (light truck which is to say the tire side wall are rated at eight plies, even though physically there are fewer plies). It rides as well if not better than my old 1985 Impala race car.