Wrapping makes them consume more?
Well, it depends on who you talk to. I've heard people say that they actually use HALF the stores when they wrap. That's seems logical to me. In particular, there was a post from a guy in Norway who uses Styrofoam bodies. He said that his bees consume 1/2 the stores than when he uses normal wood.
They don't burn as much to warm the hive. OK, OK, I know what you're thinking . . "they don't warm the hive, they warm the cluster". To that I say, I DON'T buy it. I've seen thermal images of hives in the winter time. They are definitely warming the hive. You can even see where the heat is escaping through the thinner handles cut into the wood.
Also, the question I have to ask is "why the heck would a bee consume more when he's warm?" No animal on Earth does that. Every animal that creates it's own heat needs many more calories to keep warm when it's cold. Bees don't hibernate. They metabolize honey to keep warm. If they don't have to burn as much fuel keeping warm, they won't use as much stores.
Finally, on another forum, a guy from Norway stated that the styrofoam hives actually out sell wooden hives in Norway because of their performance in the winter.