I've mentioned this before, but for me, cruising makes perfect sense for coastal expedition voyages such as Antarctica, Arctic, Galapagos, and other island-hopping destinations.
For other travel involving more in-depth exploration and adventure, it goes without saying that land-based travel is more suitable. After all, how much can one see and experience in a day or a half day at a port, rushing around from one place to another and rushing back in time before the ship leaves?
The worst is when people get off the ship for an overnight (or multi-day) overland journey and then rejoin the ship. Talk about trying to fit a square peg in a round hole!
After all, most of the world's treasures, monuments and attractions are inland and not quickly or easily accessible from the coasts.
So for me, cruising is mostly a lifestyle and is mainly about relaxing, enjoying life at sea, and socializing with other guests and crew. I don't bother running around doing and seeing everything at a port - I reserve that on land trips.