The US Dollar and international currencies

The world's most common currency / monetary unit is the US dollar. I would define "most common" to mean most widely accepted form of currency. Many goods are priced internationally in dollars - for example oil is priced in US dollars even though most of it is produced outside of the US.

Some would argue that different currencies in the world don't matter and that we should just have one common form of currency, and that would simplify things. However, this cannot work, because when the U.S or any country controls its own currency, it can control the money supply and interest rates within its country. Using a single global currency would cause sovereign countries to give up control over interest rates and therefore they would be unable to fight inflation or grow their economies as needed.

There are many countries in the world that have eliminated their own currencies and just use US dollars (for instance Panama). This is because those countries could not keep inflation under control and stabilize their currencies or their economies, so they have tied their economic stability to the US Federal Reserve and its decisions. For many smaller non-economically powerful nations, this is very beneficial because it removes the ability of their governments to just print money and create massive inflation.