How do you figure? A completely digital irreversible payment system is worth a lot in today's day and age? Also, I just read an article that was talking about a small town near the Arctic Circle that was heating their city hall building and the stuff with mining instead of oil boilers. Plus, it could replace the global banking system with all of its buildings and employees shuttling back and forth to work, etc. And it's also less energy intensive than heavy industrial processes that use high temperature heat, such as glass making. Also, it allows for new electricity sites to be made over capacity in order to grow with a local area and still have a buyer willing to take as much electricity as possible until it's needed by somebody else. And then they can just easily shut off temporarily.

Overall, mining is probably more of a net positive than a net negative.