"Display boxes" aren't shipping grade perhaps? Product boxes are usually notably far thinner unless they are already meant to bear a heavy load. Manufacturers

"Display boxes" aren't shipping grade perhaps? Product boxes are usually notably far thinner unless they are already meant to bear a heavy load. Manufacturers of direct to consumer goods seem to generally eshew "display boxes" anyway, at least in my experience. But it could imply retail packaging and package packing for others.