No, its not only for those with a carry on. We did it with several suitcases (forgot to get the luggage outside on time and were basically forced to do the self disembarkation.) IF you can manage all your luggage AND you want or need to be off the ship early, then by all means, go for it.
Carnival Cruise Lines:
Fantasy 90, Celebration 95, Victory 05, Conquest 05, Spirit 6/06, Freedom 6/08, Holiday 7/08, Victory 6/09, Valor 9/09, Dream 6/10, Splendor 8/10,Conquest 8/11,Magic 11/11,Triumph 4/12,Spirit 7/12,Freedom 11/12, Triumph 2/13 - The fire cruise
NCL Dream October 2006, RCCL Mariner OTS June 2007