We have bought it for both of our cruises and enjoyed the package, but it is mostly because we are both fairly fickle people when it comes to alcohol and we don't want to think about it.
We also enjoy trying new and different things on vacation, and the package makes that easy. If you do not like what you ordered then just get a different thing, etc.
But not everyone has the same attitude, and I met plenty of folks who were very happy they brought their fave choices on board with them. It's just a personal decision.