The idea is that cold-resistant elephants / woolly mammoth - like creatures would restore arctic steppe grasslands and promote carbon sequestration. It's difficult to sum up in a sentence but there are quite a number of articles out there on it, and it doesn't seem like the most bonkers idea I've ever heard.

And, at the end of the day, the bespoke critters are visually compelling proofs of concept for tooling & technology that they can spin off and sell for more mundane purposes.