I will give a personal perspective.
I am in a position where my travel options are now limited. A cruise ship is the perfect choice for my wife and I. It gives us the ability to see different areas of the world but to also have a convenient home base and floating hotel to work from that provides excellent accommodations, food and entertainment.
The downside is that we have become burned out on the Caribbean and have a limited time to see many parts of the world and want to use the time we have to see things and places we haven't seen before, even if it is for the short period of a port stay. A cruise satisfies these requirements plus gives me the enjoyment of keeping me on the ships that I love.