I think the biggest appeal for using LEDs is the amount of usable light vs. the amount of power. LEDs are way more efficient than any incandescent, flourescent, or Halogen for the amount of usable light they generate. That and their absolute durability make them ideal for hard use environments. From a caving perspective, it has always been that the lava tubes we explored tended to suck up the light from our flashlights and carbide lamps. The spectral quality of the LED lights is such that they overcome the light damping effect of the cave surface much better than other light sources, and we were getting better results and longer durations from D cell driven LED lights than what we were getting off big gel cel driven halogen diving lights from a decade ago.

They are not spectrally pure, but I've no problem using white LED light sources while punch telco blocks where no other light source was available and haven't made a mistake yet. Some colors are a little harder than others, but nothing too difficult to second guess my work.

I remember when the best LEDs we could use were still rated in mcd and were useless for cave work.