I use braces (and an array of hand drills) for the same reason I use hand saws. I have little kids, and when I fired up an electric drill they would run out of the room. When I fire up a brace or hand drill, they come over and ask questions and talk about how cool it is and then want to take it to their workbench and drill holes with it.
Plus they are a lot of fun. I have several braces, a #2 and #5 millers falls hand drill, and a #12 shoulder drill. The whole bunch cost me less then a good cordless electric, they all work great, and I really don't see myself having to replace them (or the battery packs) in my lifetime or anyone else's.