Great post! The picture still comes out in favour of cryptos even if you isolate what all that power draw is being used for, which is providing security and verifying ownership in a trustless manner. Traditional finance manages this by employing legions of auditors and accountants checking and double-checking every cent that moves between people and the institutions themselves.

Think for a moment about the environmental cost of all those employees: their commuting to and from work every day alone probably far eclipses the impact of crypto mining, before we even mention the buildings they have to work in, the electricity needed to run them and the massive server farms they still need to run anyway!

And not to forget alternative consensus algoriths other than proof-of-work that are far less power consumptive at the cost of a little more centralization and slightly less security, such as proof-of-stake (and STEEM's own delegated version).