Some of the previous comments are from people who don't speak English as a first language.
Cruise means: To travel in a fairly relaxed manner.
Cruiser bicycles are designed to be comfortable, but not to go fast. I would not ride one most of the time, because I like something that goes faster. But if I wanted to just ride a comfortable bike around when not in a hurry, I might ride one.
I can't speak for everywhere in the world. There may be somewhere where they have used the word cruiser differently.