Why do some space companies build "space hotels"?

At present, this idea is still in the sci-fi stage, and it is estimated that it will not really come true in the next 20 years. That may be a fantasy of my ancestors, ah, I want to build a space hotel in space, which can accommodate 6.5438+0 million people.

However, Musk's idea is more practical. He wants to move people to live on Mars, but he says it won't happen until 2050 at the earliest.