Forget how they squeeze that much power in this thing, I just want their heat dissipation technology. Besides, if it's so powerful that it can cut through basically anything, then this thing must be really hot inside (lots of energy in small mass), Hot means UV, so skin cancer is probably among the occupational hazards (as well as a dangerously cool tan). Luke got a new hand so i suppose a melanoma wouldn't be a big problem either, but the blade would be also very bright, and that would cause some nasty retina burns. Uh, looks like it's not that good job after all. Oh and this thing might last quite a while, but it must run out of juice after some time -- "wait a moment, must change the batteries". Oh, batteries, are they rechargeable, and if they are what happens if you overcharge them? KABOOM! And if they aren't then they'd probably have quite a nasty environmental impact if they just discarded them, so they must be recycled somehow. We can't get it right on a single planet, they have a whole galaxy to worry about. And what happens if you run out of spares?