Many programs would be enhanced with a accelerometer.
One game in particular would be Numpty Physics but there are many uses.
The infrared would allow you to be able to emulate the very expensive home control panels with you N810 but have more features.
The infrared Receiver would allow for remote control of the tablet via a small remote if it is docked to a larger system or a headphone remote control if it is in your pocket.
The receive can also be used for 2 way infrared remote feedback.

Anyway it is up to the programmers I an just creating the hardware.