PoW wasn't designed to be more efficient, the Nakamoto consensus type implementation exists to improve honesty and security. There is no traditional database th

PoW wasn't designed to be more efficient, the Nakamoto consensus type implementation exists to improve honesty and security. There is no traditional database that's as secure as a blockchain, it's always a tradeoff between security/immutability and efficiency. But since efficiency does matter many 2nd generation chains have moved away from PoW.