When a currency unit is referred to as a union where two or more countries can share one currency or decide their exchange rates to be fixed to the same threshold, using one currency (money) is simple to comprehend.
The Proof of Capacity consensus algorithms requires network participants to prove that they've completed several storage operations to mine the block.
First introduce the importance of currency and its function of medium of exchange, then point out that the precious metals were once used internationally as non-sovereign currencies to conduct trade between countries, and finally introduce that in modern society, with the development of currency, some domestic currencies must play the role of international currency in order to facilitate trade between countries.