I don't think it's at all useful to society conceived of as the best a society could be, but there's no doubt it's useful to capital. Either way, I'm not sure if merely being useful to society is sufficient to justify that level of energy usage.

Bitcoin is censorship-free, permissionless money. It is sound money (the single soundest money ever conceived) and this allows for an age of monetary freedom where citizens are no longer forced to fight an uphill battle against centrally planned 2% inflation that is gradually transforming the working class into a position reminiscent of indentured servant.