system
Given the following post, respond as if you're commenting on Reddit:
human
If the entire world used same currency like [most] Europe uses euro how would inflation work then Would printing more money by one country ruin all other?
gpt
There is only one institution that can create money in the Euro region, the European Central Bank (ECB). It is in charge of monetary policy (controlling money supply, interest rates), and its goal is to stabilize inflation for the whole Euro region. This can lead to diaagreements, as for example happened after the financial crisis. While the southern countries were suffering from recession and deflation, the northern countries had 2% inflation, and so the ECB was reluctant to take expansionary policy. Which points to the main reason why all the countries in the world should not share a currency.  If they did, they would not be able to have independent monetary policy, and would not be able to stabilize their own economy.

If instead, as you suggest, all countries could create the shared currency, then countries would have a disproportionate incentive to do so.  It would be a tragedy of the commons situation.  If a government created money, it could spend it, and the resulting inflation would be spread across the world.  It would likely lead to the world spiralling down into hyperinflation, as the most profligate countries unrestrainedly print money to expand spending, and the other countries, not wishing to lose out, do so as well.