That reminds me of this comic strip: https://m.imgur.com/gallery/KvypGc1

We are now the alien species in a forgettiable early season episode of Star Trek TNG.

We have been killing ourselves (and each other) to get rich for millenia. It's nothing new. But, we've also been doing many productive things for the sake of getting rich and accumulating useful capital, and these vastly outnumber the destructive things we do, which is why we're still here and by all measurements, better off and more peaceful than we ever have been previously as a species. That's one thing.

The second thing is that there's no certainty that bitcoin mining is actually causing us to kill ourselves or that it causes meaningful levels of harm. Lots of panicky hand waving around the subject, but little concrete evidence of the hysterical thing you stated.

Furthermore, energy consumption per se is not inherently bad, even for very dubious uses. It's how you procure your energy that defines harm, not that you use lots of it. If for example, we were seeing people mine bitcoin with say, solar power, or mini nuclear fusion reactors, it wouldn't matter that they choose to use energy they paid for on something some perceive as wasteful.

Actually, no, cryptocurrencies offer a way to monetize inexpensive energy production in places with energy surpluses that can't easily move energy to places that need it.