I had a gorgeous beaded black gown on one QM2 cruise - loved it but it is just tooooo heavy to take away. We did meet a couple who had 72kg each of luggage (hair clippers, hot rollers etc etc) and another woman who had 7kg of jewellery. They obviously don't travel light.
I prefer carry on size as it is just too hard to wrangle heavy cases around, not so much on board, but on public transport and in cities boarding and disembarking.