This is your first mistake: the traditional banking system does not have a security model predicated on the ability to waste power. Bitcoin does, and it’s dynamic so there’s no way to waste less power which isn’t explicitly ceding control.
The second error is treat the two as comparable without recognizing that one of them is used daily by millions of people making billions of transactions, and the other has almost no real world adoption. That matters in two ways because it’s not just that bitcoin uses more power to do so much less but also that the real financial system has higher power draw for work in addition to processing transactions. For example, Visa can do on the order of tens of thousands of transactions per second versus Bitcoin’s 7 but if you are looking at how much power they use, the figures will include running a ton of anti-fraud and other support systems which Bitcoin is missing.