I think LDing is connected with reaching a higher consciousness, a different perspective, learning to be aware.. simply taking a pill or using a machine that flashes lights etc, when you're in REM in order to induce lucidity kind of takes away part of the meaning. I'd say the path to learing to lucid dream is just as important as having the dream itself.. same thing for shared dreaming.

Actually, I've heard the waking hallucinatory state, induced by LSD is similiar to lucid dreaming in some ways? (Kind of off-topic.)