I can't speak for all proponents, obviously. From my point of view, the proof-of-work from mining is a critical part of the value of the currency, since it enf

I can't speak for all proponents, obviously. From my point of view, the proof-of-work from mining is a critical part of the value of the currency, since it enforces the scarcity, and the only reason any fungible good has value is because it is scarce. This is not unique to Bitcoin -- one of the primary reasons that USD has value is because the proof-of-work involved there; specifically, the ability to create an item that is not distinguishable from any other note of USD. If this were easy, then the dollar would be worthless, even though the actual task of "creating dollar bills" has no societal benefit other than securing the currency. (Not that you claimed it did; that is just a common objection that I am using as a strawman)