Isn't all the infrastructure, people employed, offices and everything needed to support something also a waste of energy if it can be replaced by some lines of code? Also with your energy wasting straw man remark i assume you are talking specifically about bitcoin which is just one of many cryptocurrencies and a lot of them aren't based on proof of work.
Sure, there is a lot of energy expended for the traditional banking infrastructure. It also serves multiple magnitudes more transactions than any cryptocurrency.