I'm not sure I agree. If the speakers are wireless, then they need to be plugged in to an outlet for power. Most people will not likely have outlets up high on the walls or on the ceiling. I would have an easier time running speaker wire in the walls than trying to get outlets up high on the walls or ceiling. Plus, if I ever sell my house, if I have outlets on the ceiling or high up on the walls. I think the resale value would go down unless I address it, which would be a pain to then remove and/or disconnect the romex and then patch holes the size of outlets and paint. If it is just speaker wire behind the walls, then one just has a small hole that might even go unnoticed or can easily and quickly be patched.