Yeah the only catch is that it turns out humans are really good at warming planets up, and that’s one of the big stumbling blocks to making Mars habitable. Reversing the process is not something humanity has ever done before. So why not turn one of our biggest bugs and turn it into a feature? Plus if we are going to experiment with intentionally changing the atmosphere of a planet I’d rather we experiment on a place where the entirety of humanity isn’t currently living.