One obvious advantage to customers in those countries is that they can purchase more goods than before with lower price. All of the business in those counties can trade freely. Merchandisers can get more chances than ever before and governments can also get more foreign investment. Using one-world currency also benefits travelers. As people are living a better life than before, travelling is a good choice for us to spend our leisure time. If we use the same currency all over the world, we can travel without considering exchange rates. There is no need to change money anymore.
Travel seems to be more enjoyable and attractive. When we use the same money at abroad as that at home, we will feel like we are natives. We all think we are a member of the whole world. It is good for the world peace. However, there are also some drawbacks if we use one currency. First of all, it is very unstable to use one-world currency. Once a country breaks out a financial crisis, finance of other countries will also be influenced. Like Eurozone, when the debt crisis occurred in Greece, other countries in Eurozone also suffered a lot.
This showed that it is very hard to maintain the stability of financial world. We should also see many obstacles lie on the way of currency integration. For example, cultures are different and economic performances vary a lot. Admittedly, there are some advantages if we use one currency. However, when comparing to its disadvantage and obstacles at this stage, it is not worth to say. I think we can achieve the dream of using one currency only if all countries in the world have similar economic performance.