I don't necessarily have a problem with Proof of Work, I do however take significant issue with Proof of Non Useful Work (aka common PoW). PoW was useful for being simple and dumb which made it easy to reason about.

If PoW communities are really seriously interested in losing the "bad for the environment" tag, they need to be putting significant financial effort and brain power towards developing Proof of Useful Work (PoUW) systems.