So you could use the accelerometer independently of the touchscreen for gestures like flicking ink blots or swishing the "brush" in "water" -- or maybe you can do some fancy things on the screen like tapping on the same spot for stippling (using the accelerometer to approximate height and velocity, independent of the final pressure on the tip). There's so much fun stuff to do here!
Definitely, that is what we hope developers will start using it for. We expose the accelerometer data in the SDK, so developers can get access to the data. We also use the relative pen position to the iPad to sort out some offset issues to make sure the line appears to be coming from the tip itself.
So you could use the accelerometer independently of the touchscreen for gestures like flicking ink blots or swishing the "brush" in "water" -- or maybe you can do some fancy things on the screen like tapping on the same spot for stippling (using the accelerometer to approximate height and velocity, independent of the final pressure on the tip). There's so much fun stuff to do here!