On Mon, 13 Feb 2006 00:55:24 +0000, Andy Dingley
wrote:

Convenience. You set up one gadget in the middle of the room, then you
have a horizontal datum all the way round almost instantly. Great for
tiling.

OK, but it's still a level only because it has a bubble or a pendulum,
not because its a laser. It seems that the laser part is only for
eliminating marking. That would make sense to me now.