Wax moths are not a problem after a good freeze. leaving hives in the yard, yet protected from mice, is a way to have them until spring with no damage. All my deadouts stay outside through winter just fine, with no wax moth damage. The worst thing you can do is bring them inside.
And there are simple things you can do to protect comb without Bt treatments.
If you understand how designed spores are engineered to outbreak under certain conditions and for specific larvae, it is not a far stretch to think bees could be harmed if their normal Ph levels ever were changed, for a host of reasons.
Scan down to the article about "altering Ph levels, near the bottom of the page.http://www.bjornapiaries.com/beekramblings0910.html
I'm not convinced that placing Bt spores in hives is a good thing. And any testing is always done in laboratory settings under normal conditions. And many times, this does not hold true once certain chemicals and treatments are applied in the real world setting.
Just as with most treatments, we always find out later that it really was never as safe as we thought. Wasn't that long ago that the bee industry thought coumophos and fluvalinate was safe also.