Well the point is to play with many people. The whole idea of Surface and things like it is to have several people sitting around the table interacting with it. Otherwise it'd just be a trad screen and keyboard. No need to lay it down flat and be all touch screen at that point.
The point would be to play with many people, face to face, with more possibilities regarding physical representation. Imagine you could use maps provided via DDI together with your books - don't worry about setting up dungeon tiles, just load the map from memory!
Some things to consider (because I know that much about Surface)
- The surface can theoretically identify objects via bar-code like infrared markings. It might not be impossible to roll actual dice if they are prepared properly. Though the question might be what happens if you fall off the table?
- The same principle could be applied to miniatures. Add a marker identifying it, and you can use your physical minis directly. Of course, if your existing minis don't have such markers, it's not really interesting.
- The surface is unfortunately not intended as an end consumer product. So you won't really get this experience at home anytime soon.

- The Dire Wolf didn't actually avoid Opportunity Attacks. He entered and left one or even two squares threatened by the characters.
Of course - touch displays will become more common in the future. Windows 7 has built-in support, and its launch will also coincide with the launch of new multitouch capable hardware. Apple has built up a considerably expertise with touch thanks to the iPhone, I suppose it's only a matter of time until they produce their own multitouch capable notebooks and displays.
Definitely cool stuff. Maybe another argument for going back to the Virtual Gaming Table and add built-in multitouch support? If they use WPF, it should be relatively easy. (I have just recently added multitouch capability to the software I am working on.)