It shields Governing Council members from pressures originating in their home countries; it imposes a discipline on monetary policy by having a continuous, multilateral check of time consistency and policy direction within the Council; and it counters any public suspicion that a national bias may inform policy decisions.
Thus, firms and households will hoard money as much as possible and defer actions that are associated with spending, such as consumption and investment. Put in the jargon of economics, aggregate demand will decline. That is a problem. If aggregate demand declines and sales of goods and services decrease, firms will reduce production to a level consistent with the decline in sales.