Breakability, among others, I suspect. I've never cooked commercially, but I did work at Cinnabon long enough ago that we made the rolls out of things that were identifiably ingredients. All the staff cups were plastic because things get moving pretty quick on a busy day.

The one Christmas Eve I worked in college was bananas. We had both ovens running (doesn't happen outside the holiday season) and were putting pans in and taking them out about as fast as we could make rolls and proof them.