While I think it's fair to properly account for the carbon footprint of traditional banking and state military infrastructure, it is an utter fantasy that crypto is in direct competition with them. Crypto has been steadily integrating with existing banking institutions and regulations over the last five years; and barring some kind of new free-market, secrets-based "killer drones as a service", no distributed hash table can supplant raw military hegemony (aka, the $5 wrench attack [0]).

I think crypto has a lot of socially useful potential, beyond mere speculative gambling and Austrian-school value storage, but that's in addition to the centuries of momentum in our real-world political economy; crypto-currencies are unlikely to replace that entirely, anymore than the internet replaced the New York Times.

[0] https://xkcd.com/538/