Going to financial war with your own country in the name of saving it from itself is a major thing when talking about Bitcoins power to hold government to account - but that doesn't mean government won't fight back. Early Bitcoin gave power to regular people pre-ASIC, I think we need to bring some of that back if it is entirely possible now. When everyone uses bitcoin, there will be a means of measuring Bitcoin's buying power. there will be times when its better to spend or sell stuff. The backing of bitcoin (computational power) is a little more abstract  and harder to explain than the usd which is backed ultimately by the military. Bitcoin transfers the power from the state to you, because you can just opt out if you feel oppressed.

All centralized systems use less power, and you just illustrated why they don't do anything new or useful. The power backing Bitcoin secures it and is a fundamental part of where Bitcoin gains powers of economic state immutability, it's the cost of people update the state machine that secures it from spam attacks and bad actors who would try to control it - that control bankrupts them. By consuming the power it does, Bitcoin also enables the global subsidization of electricity prices (Norway's mine closures and price increases), enables the capture of emissions (see oil and gas operations generating power and mining Bitcoin instead of flaring the gas), bolsters power grid capacity both cheaper than and with less environmental damage than batteries (Texas), and subsidizes predominantly renewables infrastructure by absorbing dynamic loads (China).