It would take extra space, but I think it would be handy to build houses with things like cable ladders and service corridors. Imagine being able to install cable TV or a new phone line without cutting any holes in walls or fastening any new wire clips to beams under the house. Imagine being able to hide all your stereo wiring out of sight and go into a narrow corridor to change it around.
Mokalus of Borg
PS - It's the extra space requirement that means few people can really do this.
PPS - The rest of us just need better ways to manage our cabling.