It does operate without those systems just fine. But even if we include those exchanges, how much energy do they spend, and how many people work in that sphere? I don't know the number, but there are not more than a hundred big crypto exchanges. And they don't have hundreds of people working inside them. That is incomparable to the traditional finance system.

Bitcoin without any way to exchange into traditional currency would be a very different scenario than what currently exists. It makes no sense to talk about it since we’re discussing energy use here and now.

So if we need to consider the resources used by the whole banking system when thinking about VISA etc, we must do so for Bitcoin as well. Otherwise we’re just playing with blue-sky hypotheticals.