Not necessarily. Nuclear energy gives GHG-free power, but 1) doesn't deal with the priced-in impact on the biosphere that will require us to change a lot of things 2) doesn't reprogram societies to become less impactful.

How exactly is fucking up some other celestial bodies going to help save this one?

gives us time and space to continue evolving without the impending disruptive setback. there is also enough free floating stuff out there it could become not worth it to disrupt the top few inches of land on this planet which is where all the irreplaceable magic happens

Some believe humans should strive to become multi-planetary species, e.g. to avoid a possible extinction event.