Proof of work is proof of humanity.
If you are not GIVING to someone else (which is all work really is) you are not fueling humanity.
It's the HARD reality of - well - humanity. How we got where we are.
The first human that invented a fishing pole, was able to feed himself, and his family/kids and for the FIRST TIME 'sell' that fish to someone else to help them feed their family! While this seems like a simple concept, it was a massive leap for humanity - PROOF OF WORK.
Tell me how they are different -