Earlier quoted context omitted.
> The problem here is, what if the demand for dollars increases? The price for gold and dollar would rise, until the worth of dollars is as high as the demand is?
> The price for gold and dollar would rise, until the worth of dollars is as high as the demand is? The name for that is deflation.
The primary function of money is its trade value, to "lubricate" the real economy to let goods and services flow. When the value is unstable, people are inclined to not spend or not accept that currency, which contradicts the free flow of it and in severe cases harms the economy.
Crypto'currencies' have the same problem. By nature, they are no currency but investment for which instability is required. No crypto bro would hype their 'currency' because there would be no pumping. Arbitrage trades are considered being for fools or insiders.