As suggested earlier in the thread, it appears to just be marketing. I was comparing insides, but I also have seen no difference in balconies. The floorplans I compared on one NCL ship are the exact same photos. So, to answer your question, the only difference I can find is about $50 per person more revenue for NCL. I suppose when it gets to the point where a ship can only be booked for guarantee fares (versus specific room selection), a person might be forced to select family to ensure there are enough beds for three or four people. Who knows?