Even looking at the usage of graphics cards specifically, is Bitcoin an objectively worse usage of those chips than playing video games? Than running ML models at Facebook?
I have done a lot of activities in video games that would require significant CO2 emissions in real life. Potentially millions of tons. So yes, it's much better. There is also a significant population of software developers that picked up programming because of video games. Economic simulation games can help you develop an intuition on how to run a company and how they work without having to risk starting a real company with the potential to fail and ruin you financially.
Meanwhile the only worthy claim that Bitcoin has is that it's a middleman for central bank money. Yes it probably funded a lot of good economic activity, but it's the job of the central bank and government to do that. If they didn't fail then Bitcoin would have literally nothing to do.
says who ? the central band and governments ? The whole point of crypto is to provide an alternative to arbitrary decisions from unelected officials.