Proof of Work (POW) is a very costly approach to electronic money. Proof of Stake (POS) or better Delegated Proof of Stake (DPOS) is a more economical solution with a better governance structure. Heck, even Ethereum is switching from POW to POS. Look for big things from EOS as it uses DPOS and offers free transactions at 50,000+ tps. It's set to become huge because it offers scaling solutions that allow parallel processing.