Travel should be a bouquet of experiences. Self-guided is our favorite, but sometimes it is not the best way to do some things.
For example, a cruise makes sense if it is taking you to places that would be extremely difficult to travel to by land. Once cruise we took hit Pompeii (Naples), Sicily, Santorini, Mykonos, Athens, Rhodes and Ephesus (Turkey). It was sandwiched around a land week in Italy (Rome and Orvieto). It would have been literally impossible to hit all those otherwise in one trip. Another cruise we took hit the Baltic, including Russia, Sweden, Finland, Denmark and Estonia. Those simply aren't easy to do by land. Cruising around shitty touristy ports in the Caribbean? Yeah, I agree with you.
All-Inclusive resorts make sense if a) there are things to see in the area that you can't see anywhere else (Chichen Itza, Arenal Volcano); b) it is a higher-crime country with shitty water. They have to be couples only, too.
Also, self-guided (foreign) travel requires a lot of energy (figuring out transportation, dining, hotels, things to see). If you go on a few trips a year, throwing in an all-inclusive once in a while can be a nice change of pace.