I've had airlift load levelers (air bags) on my truck for 9 years.
I have WD hitch but I've been known to haul a 500 LB motorcycle in the bed
of my truck along with fire wood and pull my trailer.
I use the air bags in those situations.
Also rarely I have gotten a full load of mulch. No trailer so no WD. Air bags
are handy for that too!
I went cheap and put them on myself and don't have an onboard compressor.
The compressor is nice addition if yer spoiled....
Just kidding! I have a slime brand 12v tire inflator that I can use on the
air bags as well as bikes, motorcycles, car tires etc. Cost about $20 so much cheaper than the onboard compressor which only inflates your air bags.