> POW being a race to burn as much (mostly) coal for the benefit of very few.
POW is a consensus mechanism that secures the entire Bitcoin network. At times that has represented over one trillion USD worth of value. The benefit of Bitcoin's consensus is to all the money locked up in it, without it, or even if the profit to hack Bitcoin were only slightly marginal, the whole thing would fall apart, almost one trillion in value.
It is not for the very few that consensus mechanisms reward, it is for the whole network (in the ideal case). So in a way, when Bitcoin is driven to astronomical prices, and the incentive to break into it becomes irresistible to the most powerful people in the world yet they still cannot accomplish it, it does validate the technology.