It worked well in EU because all economies there, are matured and equally strong.Developing nations with poor economies and lacking modern infrastructure are not able to reap benefit.
World currency will do faster transactions and deals but efficient economic systems with developed nations, they will dictate.
Nobel winner US economist MR. Joseph Stieglitz said, such romantic ideas can not bring prosperity, nations on equal economic strength will gain but
poor economies can not.
In India we are struggling with Globalization and experienced crisis while getting accustomed with.
Euro has lost its glory and UK is not willing to accept EURO.Why?
National interests of any nation are more important than anything.