In terms of value it all boils down to supply and demand.
Exchange Rate.
Yes, that is correct.
CURRENCY
There is no Asian national currency. Asia is not a nation. It is a continent. It has many nations. Each of those nations have their own currencies.
Nations discourage imports by tariffs or import duty which are special taxes on imports. If imports are actually fordidden it is called an embargo. Nations could also discourage imports by manipulating the currency exchange rate to make the local currency more valuable in relation to foreign currency.
Nations need a system of currency exchange rate in order to be able to tell the value of their currencies. The exchange rate is set again the price of gold in order to have some uniformity across all nations.
because they are part of the European Nations.
demonetisation
euroThe common currency for the European Union (EU) is the Euro (EUR).
A bancor is a conceived name for a hypothetical currency between several nations.
12 nations began using the euro
Nations buy foreign currency primarily to stabilize their own currency's value, manage exchange rates, and influence trade balances. By accumulating foreign reserves, they can intervene in the foreign exchange market to prevent excessive volatility or depreciation of their currency. Additionally, holding foreign currency enables countries to facilitate international trade and investments, ensuring they can pay for imports and meet foreign obligations.