I have to disagree. Gold only has value because modern civilization perceives it to have value. If we were to regress back to a primitive state, gold is next to useless. In a way, that makes it no different from fiat money.
Think about it, what practical use do people actually have for gold? It has a unique property of being both conductive and is chemically stable. This makes it useful it electronics, along with some minor uses in medicine and dentistry. However, the amount needed is actually very small and for the most part, recyclable (except for tooth fillings which don't get recycled until the owned bites the dust).
Aside from that, the fact that it is shiny and does not corrode makes it suitable for jewelry and coinage except that it is rather soft and needs to be alloyed. However, I think you will agree when I say that this is not very practical at all and jewelry really doesn't use that much gold as well.
That is the reason why gold, as a commodity, mostly just sits around in vaults. We have no reason to convert the bullion into something else. Petroleum, as a commodity, will eventually be pumped into vehicles. Copper, as a commodity, will also be eventually used. There will be a point when demand for copper outstrips supply for it. Why do you think there are people in the US who are hoarding pennies by the millions? Supply is running low, and people expect the penny to eventually be taken out of circulation as the production cost far exceeds the face value. When that happens, those copper hoarders are going to earn far more than any gold trader.
I really wish I hung on to those 1 sen coins but I don't think their copper content was as pure as the US penny.
What make Gold value is because like what you say about copper coin. But now Gold is used in all electronic devices. Gold is hard to find compare to any other ore and also used due to its conductive property. Since we know Gold is both for currency and technology. The value of gold will increase and no matter what people think about having "gold actually have no value but when people perceives it" is wrong still. Nowday, people perceived technology as most value to them, so for these high-tech gadget to appear like touchpad hand phone and high-end computer parts, gold is used no matter what.
Today's world, Gold have value and usage compare to last generations. It does not sit in the vault but in technology.