The purpose (and only purpose) of the company is to increase shareholder value. That is done via dividend and stock price appreciation. Buying the stock of a company increases demand of that stock and hopefully share price.
Honestly, it isn't. Personally, I see all of those energy spending as upkeep - some amount you have to waste in order for the system to work.
The difference between regular money and crypto money is that the upkeep of the former is mostly tied to physical reality and doesn't influence the value of money itself. In case of the latter, however, all that energy waste is a) completely arbitrary, and b) directly tied into the value of money (the more power you burn, the more you earn, and one party burning hard means other have to do as well, for the blockchain to stay secure).
Or in TL;DR: cryptocurrencies directly incentivize wasting energy. Regular money does not.