I read somewhere storing bread in a microwave makes it last longer than sitting on a shelf. Something about how the insulation or whatever that the microwave has to keep things inside normally help maintain bread longer. Don't know the science but we've been doing it for months now and we're convinced it makes a difference. Perhaps its a similar how a bread box helps.
Its just annoying to have to take all of the bread (loaf, buns...) out when we need to use the microwave for its intended purpose.