I actually think you give the parent argument just a tad too little credit. If crypto was useful as a currency (and, as you point out, if it is comparably as energy efficient as visa), that would be an effective refutation to the energy consumption argument; freeing up human resources to do something else would be a substantial net benefit of the system for society.

However, crypto does not behave to act effectively as a currency; it would be an awful idea to replace the global financial infrastructure with crypto thus the energy costs are here to stay.