the original purpose of the Surface technology was to provide a table top interface which is already in use in commercial venues with a better touch screen version of it.
Whether this will ever be practical for home use may be kind of a stretch but I can think of some really cool ways it could be used.
Imagine being able to pull out Monopoly just by swiping your hand over the interface and have the whole family gather around a life size game board and play without all of the mess of counting money and distributing tokens? Well that's one killer application for it. Just an example of how it could be used.
Again will anyone buy one of these just so they don't have to drag out the Monopoly from the closet and not have to clean it up afterwards? That's mostly dependent on the price point.
Since Microsoft is terrible at advertising I'd say it's very unlikely we'll see this in households anytime soon until a company like Apple finds a way to hype it up and get it into your living room.
Maybe with the most recent Surface II announcement, Microsoft is trying to prove that they can do exactly that.