That's beside the point, though. Knowing that Ethereum and Bitcoin consume more energy than Iceland and Switzerland respectively, why don't we turn them off until they're providing actual use? I get that markets need time to figure out if a product is useful and useless things get built all the time, but has that discovery process ever been done at this scale before? For instance, if proof-of-work ends up spending as much electricity as the United States and we still can't use it for anything meaningful, shouldn't we be concerned? I know "turn them off" sounds silly, but you can tax the miners or impose energy consumption caps until there is a smart contract out there that is arguably benefiting society.
If concern for humanity's wellbeing on this earth is a "throw away" concern to you, then maybe you can provide an argument for why everything's going to be OK? Have we fixed global warming and I just didn't get the memo?