And I'm sure that Visa + banks for settlement are still using a lot less energy than Bitcoin if you normalize it to transaction volume. Even if you only count the settlements as "real" transactions.
I'm personally mixed on crypto but strongly dislike the glossing-over of its various fundamental properties by people taking intense absolute positions about what free people should be able to do. That can get me shaking my fist at the internet, though now I mostly realize these opinions are as irrelevant as mine is, and this is good.
That drew me in with some geeky allure as something quite unique. And the scenarios like "crossing a border with a fortune stored as a memorized passphrase in your head" are cool in a cyberpunk kind of way.
But these days I'm in the "bitcoin is a paperclip maximizer" camp. I don't really want control of my money to be based on crypto keys that I could lose or have stolen with one bad mistake. And proof of work is so wildly expensive for what it does, I can't endorse it.
The PoW stuff, yeah, there is a reason it exists as you know but it is undeniably insane too. PoS is going to be interesting to see how it goes with Eth.
As a third dimension, I am very optimistic that we're on the order of 1 decade away from a huge change in energy, where solar is dirt cheap. If we see an S curve style shift to that mode of energy production, I think the PoW conversation changes a lot.
If solar becomes 100x cheaper than today's energy sources, but bitcoin mining still pays a large reward, bitcoin miners will just use 100x more energy, right? They're in a race with each other, it doesn't make sense to leave any extra hashrate capacity on the table since if you don't use it, somebody else will and they'll get more of the block rewards.
Maybe that's fine, since solar is still zero-emission, but surely there's still some cost to producing that energy (such as the space taken up by the solar panels, the cost to make and replace them, etc). Otherwise it'd be free, not just cheap.