"As the water bounces off the super-hydrophobic surfaces, it also collects dust particles and takes them along for the ride... Better yet, it remains completely dry."
That requires a sufficient water-to-dust ratio.
Driving jeeps in the Congo, or having dust blown up from dunes in a sudden gust, will require wipers. Not to mention pollen.
Hmm, that's not a bad idea! Current sprayers would obviously be inefficient because they rely on wipers to spread fluid widely over the windshield, but I'm sure that could be changed. (Such as a top pressure-rail for dispensation)
When swimming, the drag is pretty minor, most of your energy is spent on the displacement of water. That's true with fish, and with ships and boats.