A cave diver I know used some to split boulders beyond a sump where explosives were impossible, and plug and feathers ineffective - the boulders were sort of 2m-long potato shapes half-submerged in water apparently, so quite a problem. He said it was bloody expensive, but really the only practical method for that situation.
He even developed a counterbalanced winch like a shaduf to pick the broken pieces up and move them out of the way - all by himself 🙂