cavers use them a lot, and i guess that they're the kind of people who know a thing or two about the dark.
eddie mcgee (a seemingly forgotten survival author) recommends using a few of the pellets as part of an emergency fire-lighting kit (he calls it a survival kit but that generally seems to be a bit of a dirty word on here), the idea being that the gas they give off will light from the vaguest of sparks.
cheers
stuart