Mining gold is pointless busywork; we already have all we'll ever likely need for industrial production, but people continue to do it because it has value.
I consider most of what goes on in Washington, D.C. to be pointless busywork.
The difference of course is that we don't purposely pour rocks and dirt over top the gold, put on a blindfold while digging and spin around 3 times in a circle to make it more difficult to retrieve and thus claim it's more valuable, we simply dig when we believe there is gold to be found. We understand that if you agree with bitcoin in it's entirety and have drank the coolaid, that "mining" coins is necessary and thus acceptable. Bitcoin's code however is not a law of nature but a constructed set of rules that can be changed with consensus, leaving absolutely no excuse not to find more intelligent and less wasteful replacements for proof-of-work concepts later on.
I admit it; Cultist defenders of energy waste are a sort of pet peve of mine.