As others have said,
DCL's auto charge of the gratuities is a little different than most of the cruise lines. Most other cruise lines the per day/per person charge may look similar to what DCL is auto charging to your shipboard account. But on other cruiselines, that money goes to a "service fee" or other similarly named "surcharge". Those charges are pooled and divided among the staff however the cruiseline has established their policy. The cruiser has little/no control over who gets the money. (We would tip the minimum even for poor/just okay service, but when we had difficulty with a server on Princess to the point we wanted to make sure he got no tip, it was quite a Herculean effort to have tips removed from our account. And that was several years ago, I'm not sure we would be able to do it today at all.)
On DCL, the tips that are auto charged are still tips -- you have full control over the amount and who gets what. When they automatically charge the recommended tips (which is currently $12/pp/pd). That is divided among 4 positions (head server, server, asst server and stateroom host). You will get tickets showing the tip amount along with envelopes so you do still hand them to the individuals to show your appreciation. Now, you can choose to remove them entirely and tip in cash. Or you can still charge them to your stateroom account and adjust the amounts -- raise them all, raise some, lower others -- however you want to do it. We used to tip in cash before DCL started automatically applying the tips to the shipboard charges. Now, we allow them to charge the standard and add cash. It's just easiest for us and I know the cast members appreciate having their tips in a cashless form since so many have to wire cash home.