Assuming all the underlying assumptions are correct, isn’t this still comparing apples to oranges? Bitcoin does around 250k transactions per day [1] compared to credit cards doing ~1 billion [2]. And Bitcoin will only get less efficient.
The 'banking system' is a vast and comprehensive global system upon which everything basically rests, it's the 'water utility' of economics and it's far far more than 'credit settlements'.
Given that BTC doesn't really add any value and consumes 1/2 that energy, it doesn't really bode well for BTC however the comparison is done.
But, if we use the transaction count as a rough analogue, and we compare energy costs for the transaction counts, We'd come to that conclusion on a stronger basis.
The sheer vapidity of the "mining gold consumes more energy" argument bodes really badly for the intellectual honesty of the BTC proponents: At root, they actually don't care about the energy cost of the blockchain, because they don't care about it being useful, as long as their speculative gain occurs.