We need to have a single currency because of the unique service in each country around the world to spend money in different currencies and each field has the same value no currency symbols are so isolated that a currency?
We need a symbol on currency, because each country around the world use different currencies. Each currency has a different value must be separated so that the currency is a currency.
We must have the charm, because experience currency in each country all over the world use different currencies. And each genus was equal to have the symbol currency to separate that is denominated in a currency.