Some people believe that trade and travel would be much easier if the whole world used a single currency. I agree that a global currency would make trade and travel easier, but I think it would also cause some serious problems.
On the one hand, a single currency would have many advantages. Firstly, travellers would not need to change money when they visit other countries. At the moment, when people travel abroad, they have to exchange money, which costs time and money because banks charge fees. With one currency, people could use the same money everywhere. Secondly, trade between countries would be easier and cheaper. Companies would not have to worry about changes in exchange rates, which can make prices go up and down. For example, a Vietnamese company that sells coffee to Europe sometimes loses money when the exchange rate changes. Thirdly, it would be easier to compare prices in different countries.
On the other hand, a single global currency would cause some problems. Firstly, countries would lose control over their own economy. Each country has its own central bank, which can change interest rates or print money to solve economic problems. With one currency, all countries would have to follow the same policy, even if their economies are very different. For example, during the economic crisis in Europe, countries like Greece had serious problems because they used the euro and could not change their own currency. Secondly, if there is an economic problem in one part of the world, it could quickly spread to all countries. Thirdly, many people are proud of their national currency, because it is part of their country's identity and history.
In conclusion, I agree that a single global currency would make trade and travel easier, but it would also cause serious economic problems. Therefore, I do not think it is a good idea at the moment.