Actually the problem is the Eurozone. Most do want to quit the Eurozone.
The U.S. dollar is rather popular in countries where it's not even the official currency: Countries That Use The U.S. Dollar (investopedia.com)
According to the Federal Reserve Bank of New York, more than half of the U.S. dollars printed are used outside the United States—as much as 65%—to the tune of $580 billion, with the majority being exchanged in countries in Latin America and the former Soviet Union.
The British Virgin Islands and the British Turks and Caicos Islands also use the U.S. dollar as their official currency of exchange.
The British Virgin Islands and Turks and Caicos adopted the U.S. dollar as their official currency because of their close relationship with the United States.
Quasi-Use of the U.S. Dollar
The U.S. dollar is also widely used throughout the world as a quasi-currency of exchange. While it should be no surprise that the U.S. dollar is widely accepted for commerce in both Canada and Mexico, the U.S. dollar is also accepted in a host of tourist destinations including the Bahamas, Barbados, Bermuda, the Cayman Islands, Sint Maarten, St Kitts and Nevis, the ABC Islands of Aruba, Bonaire, Curacao, and the BES Islands including Bonaire, Sint Eustatius, and Saba—now collectively known as the Caribbean Netherlands.
The U.S. dollar is also used as a quasi-currency in a variety of popular U.S. retirement destinations such as Belize and Panama, and in some areas of Costa Rica. In Panama, for instance, the U.S> dollar is legal tender alongside the national currency, the Balboa, which is also worth USD $1. The greenback is also widely accepted in Nicaragua. People in the U.S. military can likely attest that the U.S. dollar is gaining widespread popularity throughout the Philippines.
For the truly adventurous traveler, the acceptance of the greenback can be tested in countries such as Myanmar, Cambodia, Liberia, major cities in Vietnam, and the Old City of Jerusalem.
The Bottom Line
The U.S. dollar is the most widely used currency in the world because of its stability. Barring some unforeseen catastrophe, the U.S. dollar will likely remain the global currency of choice until such a futuristic time when a global digital money system is invented and accepted.
So, everyone can switch over to Greenbacks.