If I'm correct, 1718MW over a year is over 15TWh, which if Bitcoin were a country would place it 78th in this list: https://en.wikipedia.org/wiki/List_of_countries_by_electrici...

I don't think Visa uses up as much energy as a small country for processing 7 transactions per second at full speed.

Using that list, Cuba and North Korea immediately follow Bitcoin in energy consumption. Cuba or North Korea alone could never hope to gain control of the network: they could not supply enough power even if they redirected everything to malicious Bitcoin mining rigs. More realistically, even a country like Saudi Arabia (with a reported 272TWh) could not control the Bitcoin network in the long term--"wasting" 5.5% of your national energy consumption is not sustainable.

This "waste" is actually a kind of security all its own.

I was referring to the entire finance and insurance industries which represent 7.2% of US GDP.

Comparing finance's shares of GDP to bitcoin hashing power is useless. The power used for hashing is at best a lower bound on how much a bitcoin based finance system would need to run.

(Eg even with bitcoins, you'd still have essentially the same stock market. You might be trading coloured coins on the blockchain, but people would still need to work to raise capital etc.)

The hashing power creates trust in settlement. Much of the financial industry is also about trusted settlement through other means. They are in fact quite comparable in that sense.

You are right that the hashing power basically produces trust in settlement.

I guess where we disagree is in how much of a proportion effort in finance is spent on producing that kind of trust vs other activities (like eg capital allocation, or hunting for arbitrage activities etc).