I fully expect that if we even had a way to calculate how much power is wasted in order to support that kind of jurassic infrastructure for every bank, Bitcoin

I fully expect that if we even had a way to calculate how much power is wasted in order to support that kind of jurassic infrastructure for every bank, Bitcoin would still come out on top by an order of magnitude at the very least. If Bitcoin is around .01% as estimated, that would mean banks account for 1% of world energy usage. I’d bet against it being anything like that high. High-frequency trading might waste a lot of energy, but that’s another silly arms race with dubious social value, exactly like Bitcoin.