You're thinking of waste too narrowly. That power wasn't available for other things, so more had to be produced to cover Bitcoin and the other things, which meant more of all the negatives that come with energy production. Does Bitcoin provide something valuable enough to human civilization to account for that? Could that value have come from a more efficient source?
Failing to account for externalities is how we get rapid ecosystem destruction (before even bringing in climate change). Those Bitcoins aren't innocent little bits on drives. They have a cost to the planet they're produced on and the life that inhabits it.
If you think you can replace bitcoin with something more efficient, please do so. The millions of people who use bitcoin every day would gladly switch to a cheaper version if it was truly just as good.
I don't take it as a given that Bitcoin is a good solution to the problem those people solve with it. The best of the bad solutions is still bad, and Bitcoin isn't looking too good by its power consumption. It's okay to stop, really think about a problem, and find a good solution instead of charging ahead with a bad one oblivious to the brick wall ahead.
What do you think is the best way to store+exchange value across borders in a way that can't be censored or reversed by any third party and doesn't require trusting or asking permission from any third party?
Made an account just to upvote your comment. This is an incredibly powerful point that appears to be completely missed by the majority of threads I'm seeing. Maybe PoS will turn out to be effective and reduce energy costs for cryptocurrencies, but there is absolutely nothing like them. The anonymity of money is valuable for any free and open society, and Bitcoin is currently providing that to anyone willing to create a wallet.
Failing to account for externalities is how we get rapid ecosystem destruction (before even bringing in climate change). Those Bitcoins aren't innocent little bits on drives. They have a cost to the planet they're produced on and the life that inhabits it.