Yanis Varoufakis in Project Syndicate:
The euro’s primary purpose was to facilitate integration by eliminating the cost of currency conversions and, more importantly, the risk of destabilizing devaluations. Europeans were promised that it would encourage cross-border trade. Living standards would converge. The business cycle would be dampened. It would bring greater price stability. And intra-eurozone investment would yield faster productivity growth overall and convergent growth between member countries. In short, the euro would underpin the benign Germanization of Europe.
Twenty years later, none of these promises has been fulfilled. Since the eurozone’s formation, intra-eurozone trade grew by 10%, substantially lower than the 30% increase in global trade and, more significantly, the 63% increase in trade between Germany and a trio of European Union countries that did not adopt the euro: Poland, Hungary, and the Czech Republic.
More here.