Historically gold existed as a currency because it had some useful properties:
1. Unusual appearance;
2. Relatively scarce;
3. Inert;
4. Fungible; and
5. (This is a big one) Density. Up until the modern times it was the densest material someone could be expected to have (eg Iridium, which is denser, wasn't common in the Middle Ages). Why does this matter? Counterfeit currency, as was a problem with anything based on silver.
Currencies only have value because people give them value.
There's a lot here but this jumped out at me:
> The Germans fell into a policy of financial excess, ending in hyperinflation. Their experience was considered one of the object lessons proving the value of the gold standard.
No mention of the Treaty of Versailles here. Germany was forced to pay war reparations. Those were denominated in deutschmarks. Hyperinflation actually "solved" Germany's reparation debt problem. In a way, Germany was incentivized for hyperinflation. The importance of that cannot be overstated.