DKS
Wax on, Wax off.
Its not the laziness factor, its about marring the finish. rubbing a towel around the car has the chance of dragging dirt across the finish causing marring. You dont have this issue as much with washing because the soapy water is a lubricant and the dirt gets suspended in the soap to keep it off the paint.
Don't most of the gas ones blow the exhaust out with the air? I know some of them do for sure. I'd be skeptical to use something that is blowing exhaust fumes all over my paint. But, from what I've heard the battery ones suck. When I was shopping around I was told that if you get one that's powerful enough to work, it will eat through the battery faster than you can get the car dry, but IDK, I'm just going off what I heard/read.