Yeah, I can't say that I loved having to spray down and tumble dry all my outerwear after every few uses when I went boarding. There actually is a substance similar to this that is used by the British military, specifically SAS I think, for some of their gear but last I saw it was ridiculously expensive, though this may be the evolution of what the guy responsible for that product made back then. I know at the time they were talking about using it to make spill proof shirts and slacks eventually.
Regardless, there are a lot of great applications for this over time if it's durable. Forget just windshields, you could coat an entire car with this if you found a way to include it in the painting process, make even better stain proof garage floors, carpets, whatever. There are a ridiculous number of possibilities depending on the exact properties of this stuff.