Except one minor (read catastrophically major) flaw. It's extremely wasteful. It's nice in theory but it has no limit to the amount of energy required to conduct a on-chain transaction. Further, the billions of dollars wasted on electricity each year (above and beyond the energy required to conduct transactions) is absurd.
POW is nice in theory, but terrible for our ecology and ripe with economic waste and misalignment of incentives.
It's great that it wont ever be hacked. But the flaws are too great to ignore. POW is not the future.