I'm not sure I understand why expending energy to mining more gold than we actually need, so that the excess can be used to represent money, is worse than expending engery to verify scarcity and transactions. If the argument is efficiency then there are so many other examples of society being inneficient, why is it an issue for bitcoin but not for other industries?
The world hasn't used the gold standard for 50 years, and arguably even the Bretton Woods arrangement itself is a pretty significant departure from the gold standard. It's not like the gold standard proved to be historically a very effective basis for economic activity, so trying to say that Bitcoin is exactly like the gold standard isn't a strong argument.
Historically, the main advantage of the gold standard is that it doesn't require a high degree of state capacity to function, and of course throughout most of human history, state capacity was pretty damn low. But we live in an era where states largely have high state capacity, which allows us to move to economic standards that require that capacity to function effectively. Trying to argue for a system that increases inefficiency so that it can eliminate the need for a high state capacity government feels like a step backwards to me.
Apropos of anything else, no one is arguing for a return to the gold standard, yet Bitcoin enthusiasts love to talk about its role as an alternative to fiat money. Sure, you can make the argument that gold mining is as inefficient as Bitcoin [1], but it's a strawman argument at best because there's no advocacy for the gold standard.
In the case of BTC and gold, mining puts downward price pressure as new "resources" are "discovered". Miners need to sell the gold/BTC to recoup the cost associated with mining. In BTC it's energy, in gold it's equipment/labor.
In a free market, we would expect the inefficiencies to be removed from the economy over time. New competition, new ideas, etc.
In the case of BTC, removing PoW would remove the downward price pressure it sees today. The miners don't really want BTC, they want USD.
The gold actually exists. I have some in my computer and my phone, it can be used for jewelry, decoration, and has thousands of years of provenance to ensure its value is roughly stable.
Bitcoin is none of those things, it's a cryptographic exercise in waste, producing nothing of value.
