Banks and Bitcoin serve radically different purposes. (Try getting a mortgage from Bitcoin!) A more appropriate comparison would be the percentage of bank energy that goes to payment processing, which is probably pretty low.
One major thing other than move money that bitcoin does is print it. If you also look into the complexities and inefficiencies where our money/debt come from I think you'll find they've very high indeed.
What about all those air conditioned buildings with all those eating, breathing, commuting human beings everywhere? Bitcoin looks pretty competitive to me against that.