Regular emergency exit signs might work and make sense during an annoying fire drill, but what about when there's, you know, a real fire? When you've got to crawl out of a smoke-filled hallway, it might be a bit more disorienting and harder to see those signs above the doors.
That's why the Halo Light makes so much sense. Instead of simply glowing above the doors, it beams down circles through the smoke and onto the floor, allowing people crawling out to easily find their way. Unless you have some sort of sophisticated escape system, this Halo Light sure beats the types of exit signs we see now, and it should be only a matter of time until they're implemented in buildings.