The idea of regularly putting grubby fingers on a screen is pretty awful. It would get so crusted up so fast that you'd have to get a windshield scraper to clean it.
At least some people may want touchscreens for first person shooting (FPS) games if touchscreens can handle finger poking. :-)
I'm not sure how good this would work. At least, the front of the touch screen would need to be pretty sturdy, if I consider the violence if my mouse movements sometimes. Also, I am not sure how one would want to replicate fully used 8-button-mouses :)