Bingo. Over 7% of our entire economy is in finance, meaning people keeping records of where we put our money, Banks by and large. Once block chain really becomes efficient, we will not need any more banks to keep those ledgers, and then money can become international. But the GPU and electric costs are still pretty high, and transaction times are quite slow relative to credit cards etc. Yet I think there is more to be perfected in the block chain itself and perhaps proof of stake might turn out to be sufficient to assure the security of the system. We are still in the "if man were meant to fly he would have wings" point in Cryptocurrencies.