The reasoning for the commercial farms to have them makes sense. They don't get as hot in the summer so less energy needed to keep them cool, they don't have feathers (not even the "hair") so no need to pluck so that saves energy, and then, chickens use protein to produce feathers, so chickens that do not produce feathers have less overall protein requirements over their lifetimes. Plus, when you process and pluck 10,000 chickens at a time, that produces a LOT of feather that has to be disposed of somewhere, these chickens don't have that issue.Gahhh whyyyy!!!
I'm not entirely sure about the people that have them on smaller farms and their reasoning. Personally, I think they look neat and think it would be awesome to get that gene into some of the giant oriental game birds... have little dinosaurs running around... They act just like normal chickens, they take dust baths and preen invisible feathers and everything that a normal chicken does, except for flying, not sure if they even attempt that or not.