Pretty interesting. I can't think of a great use for it besides the one Wacom and other high-end input tablets already use (the harder you press, the darker mark you can make with a virtual pencil), but then again, I'm not an award-winning user interface designer (just a pretty average user interface user). Who knows what Apple could come up with using an interface like this-- maybe flip through CoverFlow albums front-to-back as well as horizontally?
Of course, like all patents, as AI notes, Apple has no obligation to actually use this design in any of their products. But just in case you needed any more hints that they're not walking away from a touchscreen interface anytime soon, here you go.