Although it would work for Gummint science stuff, I wouldn’t see a commercial reason at all involving Mars; the asteroid belt is a different story.
Sticking with the space treaty is foolish. Anyone who believes that a nation like China would pass up the chance at the mineral wealth of the asteroid belt is fooling themselves.
The only thing stopping China from doing it now is the lack of ability. American corporations probably would have been well on their way without that damned treaty.