Lacking an understanding what money is and does, you cannot begin to understand why gold is historically the best money. The qualities that all good money will ideally posses are:
- Durability – does it rust? rot? corrode? melt?
- Divisibility – does its value change when divided into smaller units? Two halves of one cow is not nearly as valuable as one whole cow.
- Portability – Can it be easily transported?
- Non-counterfeit-ability – the reason for this attribute should be obvious
- Homogeneity – are different units of the same size essentially identical? Not all oranges are identical, nor are all cows. OTOH, gold is gold is gold is gold.
Gold has been the preferred form of money for 5000 years because it is a commodity that possesses all of these qualities.
All fiat currencies are portable, homogenous and divisible. But they are easily counterfeit-able, (just crank up the printing press and make more!), and not remotely durable.
Look at the list of hard commodities traded on the Chicago Mercantile Exchange and you will see things that have been used as money over the millenia. They all have drawbacks of one sort or another, except for gold.
Silver is closest, but it has industrial as well as monetary uses. This dilutes its value as money. Platinum is similar to silver, but much rarer than gold. In fact, all the industrial and rare-earth metals share gold’s qualities, but they all have significant industrial use. Gold is nearly useless as an industrial metal. Strangely, that lack of industrial value actually increases its usefulness as money.
Oil is very close as well. It doesn’t degrade over time, is very easily divisible, and impossible to counterfeit. But because it is a liquid, it tends to be difficult to transport. And of course, like silver, it also has great industrial use.
Salt used to be money, but it lacks durability. Get a good rainstorm or flood and your money literally dissolves before your eyes. Livestock and agricultural commodities have also been used as money, but they all lack one or more of the qualities that gold possesses.
Commodity-based monies impose fiscal discipline on governments. If a government wants to run a deficit, they have to come up with a way to collect actual money. They can take it from the people by force, but they cannot create it out of thin air.
Imagination-based monies, (fiat), impose no such discipline. With a fiat money, government is free to run up huge debts, and then pay them off with money they create out themselves. This makes it much easier to do incredibly stupid things, like start crazy wars, support military bases in 159 countries around the globe, and bail out giant banks that make crazy, risky bets and lose.