No it isn't. If that energy is cheap enough to be used for securing Bitcoin then it can't have been used for something "useful" (in your opinion). Energy isn't fungible and transport costs exist. The immediate benefit is securing and making possible an open, permissionless digital financial system anybody can use. That is an absolutely stunning technological innovation. Proof of stake is the perpetual motion machine scam here.
The massive amount of stranded hydro that Bitcoin was soaking up in China, when mining was banned was that energy magically teleported to NYC to power people's TVs and dry their clothes? No, it's now sitting there unused with no buyers of last resort. In fact, that being sitting unused is now subsidising the fossil fuel mining by lowering the relative mining difficulty.
Mining is responsible for a rounding error in emissions, if it disappeared tomorrow it wouldn't even make a detectable dent.
Fossil fuels are bad. Fossil fuels being used for mining is bad. That doesn't make Bitcoin bad.
Sure, when we have a 100% renewable grid where Bitcoin neither takes away renewable quota, add dirty energy, cause grid to have to expand, or causes issues when TWh of heat is vented, and it is then adopted for legitimate reasons and not primarly for speculation and scamming, then Bitcoin goes from extremely harmful to mildly interesting.
Yes there are cases where they buy good power plants, but they also power from grid and buy dirty power plants. Even in case of good power, the investment should instead be made to make this power useful. Heck, folding at home or similar would be a hell of lot better usage.
But that isn't where we are. We're in a huge energy crunch, and having to go back on green policies because of it. During this time, ANY consumption is bad, and no, regardless of opinions on its usefulness, Bitcoin does not yet contribute in a meaningful enough way to sacrifice other utilities.
So yeah - I agree with you that we can waste power when and only when the vast majority of dirty power has been replaced.
"ANY consumption is bad" You really aren't getting this are you. Energy in place A can't be magically transported to place B where it's needed for what you bless as acceptable usage. Bicoin miners aren't using grid energy. They're using energy that CAN'T be connected to a grid. Bitcoin is a fantastic use of energy regardless, just because YOU don't need to use it or think so doesn't make that the case.
2. Some miners - mostly China, which is no longer mining - buy decommissioned power plants and mine "off the grid".
... But, surprise surprise, these decommissioned power plants were previously used. People generally do not invest in building power plants that cannot connect to the grid, as the power plant needs to make money. While it never became a thing in the US, energy trade is a big thing in the rest of the world - see e.g. the European Energy Exchange.
The people that tripped over a hydroplant that was built only to power e.g. a remote factory that has shut down and nothing else, account for a very, very, VERY small amount of miners.
Considering that Bitcoin mining consumes TWh in the scale of a small country, those few fairy tale cases just don't matter. It's a cute way to try to justify the environmental disaster Bitcoin mining is, just too bad it doesn't hold.
The massive amount of stranded hydro that Bitcoin was soaking up in China, when mining was banned was that energy magically teleported to NYC to power people's TVs and dry their clothes? No, it's now sitting there unused with no buyers of last resort. In fact, that being sitting unused is now subsidising the fossil fuel mining by lowering the relative mining difficulty.
Mining is responsible for a rounding error in emissions, if it disappeared tomorrow it wouldn't even make a detectable dent.
Fossil fuels are bad. Fossil fuels being used for mining is bad. That doesn't make Bitcoin bad.