The view that the member states remain sovereign is controversial. This is an error. The members are delegating powers. This is true for all members, but particularly for the larger European powers. Unhappy history suggests that monetary unions, unaccompanied by a credible merger of sovereignty, do not last, examples being the Latin, German-Austrian and Scandinavian monetary unions.
Money is political, particularly in the modern world.
Yet Emu is an attempt to separate it from politics. This is true in two respects. First, decisions at the EU level are made by guardian bureaucracies and inter-governmental committees, subject to the oversight of a remote and feeble parliament. Meanwhile, democratic politics is almost entirely confined to member states. Second, the EU has established an unprecedentedly independent central bank, one entitled by treaty to determine both its goals and the instruments it uses to achieve them.