Hordes of watchdogs from newspapers and news agencies, in banks and investment houses follow the doings of central banks all around the clock. I am not sure that all politicians on the Continent are monitored as strictly by a parliament as central banks are by the general public.
And third: anyone who draws up a constitution for the monetary system has to answer a fundamental question: what role is currency supposed to perform? Is it to provide, by its sustained stability, as good a long-term precondition for economic success as possible, even if it is known that monetary stability alone will naturally not suffice?