Imagine this. You are planning a 3-country trip. London to Paris to Moscow. Even though these countries are so close together, you would have to convert all your money. Your home country to UK. Convert to pounds. UK to Germany. Convert to Euros. Germany to Russia. Convert to ruble. Russia to your home country. Convert to your currency. Throughout that short 3 country trip, you had to convert 4 times and each time having to pay a lofty fee.
Now, what if we had currency that everyone used? Let's call this currency the Nummus. Now what would this trip look like. Your home country to UK. UK to Germany. Germany to Russia. Russia to your home country. Look how easy and more convenient the Nummus is than if we had all those currencies! International trade would also be easier as all the countries trading would share a currency and have no need to convert currencies (which makes international items cost more becuase of the conversion fees) when they are already overpriced because of shipping fees and tariffs.
A global currency can also help us with growing a developing nation's economy. This is because its a stable economy for the country to use instead of their own which may hyperinflate or become unstable like countries such as South Sudan who has one of the weakest economies in the world because of their lacking funds to build their own economy after a large civil war. But you may say, "Won't this bring down the economies of the other countries?". But, should we deprive the economic rights from those people from poor countries just because we wan't our country to be wealthy? That wouldn't be fair, would it?
Right now, the world is going through an economic crisis. Houses are up. Food is up. Everything is up. Now, this is because of our unstable economy. But is we adopted the Nummus, then we could get out! How do we know this is true? Well, inflation would be stopped if we adopted a global currency! One of the main causes of inflation is government policy. And since the Nummus is governed by a global bank rather than just a national bank, then they won't make the foolish mistakes that national banks make which lead to inflation. So then a global currency might be the answer to inflation.
If enough countries use the Nummus, then all of these effects mentioned will take place and the world will become a better place. It will let us not have to worry about every item we put in our shopping carts, let us fully buy a house again, let us live like we used to! So maybe, thats all we need to get out of this hole that is the economy.
Eric Fontinelle, 2023, One World, One Currency: Could It Work?, https://www.investopedia.com/financial-edge/0310/one-world-one-currency-could-it-work.aspx
Iryna Tsymbaliuk, 2024, What is One World, One Currency?, https://rates.fm/invest/one-world-one-currency