To me it looks like it would definitely waste product. And if I would have the same luck as when I roll paint on walls, I'd end up with armor plating on my car! I'd also be worried about an even coating, as I have to keep going over an area many times when using a roller with paint to even it out somewhat.
I'll stick with applying wax by hand or PC where I can get quick, even, and very thin coats. Especially with products like NXT, #20, etc...
But, other people may find a use for it. And they may have better luck than I am portraying here. If someone tries this, I'd be interested in results just to satisfy my curiosity.
Dave