What damage? Ceramic treatment twice a year keeps my paint protected. Touchless does work great for what I use it for. Wash bays around here use city water, which is hard and leaves spots. Touchless wash finishes with DI water for the final rinse, then an air blower removes almost all the water.It doesn't work great for anything, it's just what some might find acceptable. Just because you can't see what it's doing to your paint doesn't mean it's not causing harm to your paint.
If getting road grime/chemicals and dust off your paint is your main concern and you don't care if it's clean, you're much better using the wash bays to spray it down.