I think gfodor is asking something more along the lines with "What can you do with gold that you cannot do with anything else you can buy?" There are valid answers to that - gold is a catalyst in several chemical reactions that won't work with any other metal, it's corrosion resistant, it's shiny, it's a very good conductor that's quite malleable. But I'm with him in surmising that if people only used gold for its metallurgical properties, absent any historical sentimental attachment, the price would drop 99.9%. Gold is actually quite abundant; 190kt have been mined so far [1], most of which is either locked up in jewelry or being hoarded as an investment, so if people ceased to believe it was valuable there'd be a very large oversupply for the few real industrial uses.
[1] https://www.gold.org/about-gold/gold-supply/gold-mining/how-...