Next to the ability to light up and roll away, there are two features seen increasingly in computer keyboards: waterproofing and silence. The "ReallyCool Keyboard" manages to accomplish both at the same time.
And really, why shouldn't it? In this day and age, these should be standard specs for all models. Many are aimed specifically at such professional settings as courtrooms and medical facilities, as Dvice notes, but there's really no reason that they shouldn't be used everywhere. The ReallyCool Keyboard even has backlighting so you can type in the dark while spilling coffee on it in silence.