Quote from Grandluxe:
Maybe you should realize in virtually all of history, political union always comes before monetary union and inevitably this always meant violence and war. Look at China, today we think of it as a homogeneous nation but it fact 2000 years ago, it was made up of 14 countries which all had their own language often mutually unintelligible, currency, customs, units of measurement,etc. It took 500 years of horrific warfare before the first emperor of China wiped out everybody else, standardized everything and another few centuries to mold it into a homogeneous whole. Arguably it is today the longest lasting supranational entity in human history. How many people are you willing to see killed to achieve this kind of integration?