What's a bit more interesting to me than the fact that it vibrates is that it has a 3D accelerator chip. The graphics core is driven by an industry-leading 1 million polygon*/second graphic accelerator chip, with the ability to allow the game's background to be displayed in 2D, while the people and other elements are shown in 3D. Now that is pretty nice. Innovations like this will have a great part to play in the sorts of devices like these we will no doubt start to see as time goes on.
Seemingly, the vibration effects DO add some extra dimension to the game, with for example, the mobile phone vibrates as the player's car bumps over gravel or other unpaved surfaces. But it seems clear that this is just the first generation of many such mobile phone / portable games system fusions.