That's my whole argument for gold. The finite supply isn't socially constructed, and getting more requires building real infrastructure.
2. What do you mean by "real" infrastructure? Crypto-mining rigs are no less real than actual mines.
My argument would be that gold's value is as much a social construct as that of crypto; value is just a function of supply and demand.
I'm guessing you might post that there is a third input: utility. "Currency" is one use for gold, but can certainly serve many purposes, whereas crypto coins are strictly used as currency. That fact is presumably taken into account by a coin's price; nonetheless, it still has whatever value the market says it has at any time.
Meanwhile a TSA scanner's beep get treated as "this person is bringing a problem.".