no, it isn't. Over the course of a few decades, a kilogram of methane has the greenhouse impact of ~50 kilograms of CO2 because of the different absorption modes methane has that CO2 doesn't. If terraform leaks more than a few percent of their product into the atmosphere from carelessness (who cares about tracking such a low value commodity?) Then this is worse than just leaving the CO2 in the atmosphere. I really wish they'd address this fact more. Some possibilities:

-The hydrogen half is still a great way to make hydrogen for industrial processes

-The methane can be used on site of production for organic chem feedstocks

-Many new rockets are using methane as their fuel, using it at point of origin instead of transporting through leaky pipelines and trucks.

Any analysis along these lines would be reassuring that this isn't going to be a net-negative, climate wise.