No government will give up its own currency distribution rights!
You refer to the euro, there is no favorable factor for the EU economy, and some European countries have economic crisis!
A global currency has a limited effect on the development of the economy!
There is 100% chance of having one global currency in the future. There are thousands of currencies in the world and when you visit a country you need their currency. It is difficult to change your local currency into dollar and then your required currency. You will have to pay exchange rate two times. So it is much better to use bitcoin as global currency.