Haven't used it on
DCL, but at the parks, the MagicBand is so much more convenient than the cards. On a trip last year, we realized we forgot the bands at home and used the cards for a few hours and then dropped the money to buy bands at the parks. Of course, we bought the older bands and not the MagicBand+, so we are considering buying the MagicBand+ so that we don't have to drag around lanyards on the ship. The bands are waterproof and innocuous that you can leave them on all day.
(And yes, on DCL, they call it the "DisneyBand" because the term "MagicBand" is trademarked in Great Britain and possibly Europe. Same product; I suspect at some point, the parks will start using the term "DisneyBand" as well to avoid confusion.)
One question: How do the bands work for getting teens access to Edge and Vibe? Would hate to buy the bands and then still have to have them tracking the lanyards for the teen clubs.