Who actually calls it a "shipper"? Hot Toys? Collectors? Is that the official designation for the brown box, or one that's been informally applied to it because that's how Sideshow views and uses it?
Was it actually intended to be used as a shipper, or is its purpose to protect the art box?
I wouldn't actually care to have my figures shipped with only the outer brown box as protection, if it arrived undamaged, but I've received too many dented, creased and perforated art boxes in the past. Neither UPS nor FedEx can manage to get one to me without some degree of damage inflicted to the product box.