I'd been wondering the same thing. My glass technology knowledge is weak.. Out of ignorance I wonder whether there's any difference between glass tempered for residential use vs glass tempered for automotive use. I do "know"
that windshields are constructed of laminated glass with a layer of some kind of plastic inside, but are side windows and RV windows constructed similarly? I dunno.
So far as the potential for sliders leaking at the seals: my bus already has horizontal sliders and the seem to do alright. They leak some air, as would be expected. But recall that it's not abnormal for a house to be designed to withstand 40-70 MPH winds either.
I guess it's harder to get that sleek rounded-corner aluminum frame in a residential window. But a person might not care for that anyway!