That might increase the desire to switch funds in certain situations. In that case, the exchange rate would tend to fluctuate more. At times, one also encounters the argument that the euro area -- as a large economic and currency area -- will be relatively less dependent on foreign trade, particularly as the structure of exports is heavily diversified.
The outcome would be -- at least, according to the standard textbooks -- that the euro/dollar exchange rate is not as important for Europe. This argument is undoubtedly fundamentally correct and also of significance. The comparison with other major currency areas -- such as the dollar area -- has only limited validity, however.