They won't clone a mammoth from DNA. Woolly mammoth remains frozen in permafrost are too degraded. They'll genetically engineer an elephant mammoth hybrid that would be almost identical to its extinct ancestor.
We should go for it, I do agree with the skeptics who think this too little, too late to have any meaningful impact on global warming. First it's super cool; second given the strong correlation between the spread of modern humans and the extinction of megafauna we are probably restoring ecosystems we destroyed and third, it would be so easy to kill them all again there is no danger of them becoming an invasive species.
It's an attempt to rebuild the permafrost by bringing back the natural habitat and providing a chance to save the endangered Asian Elephant.