I am not up to date with the latest developments. Is POW, as in blowing away heat, fundamental to all coins? Is there such a thing as "Proof of Service", or "Pr

I am not up to date with the latest developments. Is POW, as in blowing away heat, fundamental to all coins? Is there such a thing as "Proof of Service", or "Proof of Meaningful Work"? Tho, I assume everything can be exploited by twisting it into meaningless, but more competitive "work", coming down to just generating heat...