Why is almost every computer mouse sold today "wireless"? It is a major nuisance (and?

As a rule I always prefer wired devices myself. However I have a Dell Zino attached to my TV that I use for Netflix & DVD's. It's nice to have a wireless keyboard and mouse for it because I can control the computer without having to get up and walk over to the computer. My mouse has a charging stand and I have 2 sets of rechargable batteries for the keyboard.