On a newly washed car it's not there to clean but put a decent wax coat on.
As an example, if I wash & dry the car using wash'n'wax then drop a cloth on the bonnet it stays there.
If I use waterless, I'm currently using Mantis because I bought a job lot and it has carnauba wax, then drop the same cloth on the bonnet, it slides off.
As you hint, I've never used waterless to actually clean, I'd be scared of minute scratches.