Since the beginning of civilization money has been necessary for financial transactions. The volume and complexity of those transactions has fueled the need for bigger money supplies, and for issuing them in different forms.
The money supply zoomed in industrial economies. Activities that a farm family might have done themselves a hundred years ago now require several transactions a day. But computerized trading of stocks and other financial instruments in mini-second intervals blows monetary froth like nothing else before it.
Today a great deal of money and the valuations it represents are only strings of zeros and ones in computers somewhere. In earlier times, it was all a solid material, a metal like gold or silver preferred. Rulers in a pinch would often cheapen the metal in coins, called debasing the currency, an earlier form of inflation.
When people fear that the value of a currency will decline, they flee to gold or other precious solids. The quest for an absolute value standard for money is never-ending, although useless. Even the value of gold varies over time; it is not constant, just more stable than a currency whose value is fading. And currency values themselves change; else we would not have foreign currency markets.
A stable value global currency is obviously preferred for global trading. However, local currencies are preferred to keep trading (and much economic activity) within a local area.