That's surface habitation, not an orbital station around the planet or one of its moons. The problem with using a space station as a waypoint on the way to and

That's surface habitation, not an orbital station around the planet or one of its moons. The problem with using a space station as a waypoint on the way to and from the surface of a remote body is that it make the mission more expensive. For example, the Lunar Gateway increases the delta-v requirement by 15-20% (can't remember exact number) compared to a more direct mission. Which then, all else being equal, increases the total mission cost by much more than 15-20% because the rocket equation always wins. And that's just the actual visit, we're not even considering the cost of putting the station there in the first place. So I keep going back to, why a space station? If we're going to spend all that extra money on turning hydrogen and oxygen into hot water, why put it toward a space station out in the middle of nowhere instead of, say, more time or more equipment on the surface of the body? Also, IIRC, none of Elon's proposed mission architectures for going to Mars involve an orbital station. And, while SpaceX did get the Artemis lander contract, they weren't involved in the decision to have a Lunar Gateway.