Yes, and that doesn't really address the issue of proof of work blockchains wasting energy. With BTC specifically, the incentives are there to waste as much energy as possible as the difficulty and price goes up. Yes, you try to do more work with a unit of electricity, but the net incentive is to add more and more.
Then what? Do you end up with this problem? https://news.ycombinator.com/item?id=26226470