You may think I'm exaggerated but sad to say I am not:
In Venezuela, where rampant hyperinflation and subsidized electricity has led to a boom in bitcoin mining, rogue operations are now occasionally causing blackouts across the country. The world’s largest bitcoin mines are in China, where they siphon energy from huge hydroelectric dams, some of the cheapest sources of carbon-free energy in the world... By July 2019, the bitcoin network will require more electricity than the entire United States currently uses. By February 2020, it will use as much electricity as the entire world does today.
It might not be necessary if other companies follow Valve's lead and reject Bitcoin, and the market finally crashes, but outlawing or at least drastically regulating mining needs to be a debate topic starting now. Trouble is, when the US President literally thinks climate change is a Chinese hoax and the Russian President is benefiting from Bitcoin, I'm not sure which global leader is qualified to start (and sustain) that conversation.