Gold has a lot of practical applications now (although is of course still treated as a ‘precious’ metal of value), but hundreds of years ago it was just a shiny metal. Why did it demand value, because of it’s rarity? Why not copper, because it was too easily found? What made it valuable ahead of other similar metals?
It’s not useless, before stainless steel it was one of the few inert metals that could be used for food handling.
Aluminium used to be more valuable than gold, Napoleon had his most honoured guests served food on aluminium plates, while lesser guests had to make do with solid gold.