Banks aren't magic. If Facebook wanted to, they could start a bank. Anybody can start a bank. There are regulatory costs, but any business of reasonable size

Banks aren't magic. If Facebook wanted to, they could start a bank. Anybody can start a bank. There are regulatory costs, but any business of reasonable size could comply with those costs. And banks "make money out of nothing" because bank deposits substitute for hard currency. If a cryptocurrency became standard, then someone could create an institution that accepted cryptocurrency deposits, and it would function exactly like a bank.