I'm not the best suited to explain it, but the die roller is basically that - digital "die" that can be rolled and used as a random element in a system game. Think the two die you use in Monopoly to move, except much more complex.
Xillen's post in the FAQ-in-progress, here
, can probably enlighten you a little more on the subject, though I would actually advise you on asking him yourself. :)