Stuff like this happens with excess food too. https://sixfootjournalism.wordpress.com/2016/05/27/kathmandu...
The fact that the domes had all the fittings necessary to let them be blown up makes it seem like that was the plan all along, that the whole project was just some kind of busywork to make it seem like they were working on a solution. Feels not unlike the impotent "ethics teams" and DEI teams that big corps set up. Pay some people to do research and write reports and then, when someone is asking what you are doing about X issue, you show them that you are "working on it". Rather than simply executing any of the many legitimate solutions people have already come up with for fixing societal woes.
It seems there's no point sending it to deep space unless you're going to transplant it all on a new planet.
It also forced Dern's character into action, since he would have to return to Earth since his job of caring for the pods was about to end.
The film reminds me somewhat of 'Interstellar' — a once verdant world going dark and expelling the hero.
If you need an analogy, think of unsold books. They get their covers torn off so they can be reported as “destroyed”, and then be issued a refund. (You’ll sometimes see a message warning you about purchasing paperbacks without front covers in books.)
In the movie American Airlines made an insurance claim, or made some other claim of loss on the trees, and so they now have to destroy them.