I had an interesting conversation with my co-worker about refrigerators. He used to work in a micro-biology lab. They had several freezers, some upright, some chest style, and they were outfitted with alarms. The chest freezers had a distinct advantage in maintaining temperature while the uprights were more convenient. If you opened one of the uprights for more than several seconds you started getting alarms. The chest freezers were much more forgiving, and in the event of a power failure, you could just open the top and dump in dry ice. They didn't care about energy efficiency but there is some overlap in that what sets off the alarms quickly must translate into increased energy consumption. Looking at it that way this is a real world confirmation that the chest freezers are easier to keep cool and must be more efficient. They were correspondingly less convenient.
Regarding residential chest freezers, I don't think that they auto defrost so that is a chore that must be done but since some find it beneficial to disable auto-defrost, that may be a selling point.