The euro zone has not yet been made crisis proof, so the ECB is still at risk of having to function as a crisis-response unit, a risk to its independence

Certain issues like the lack of credibility of fiscal rules or the harmful sovereign-bank nexus still have to be adequately addressed

fighting crises forces unelected central bankers to take political decision, which are difficult to square with democratic principles and may go beyond banks' narrowly defined mandate.

Acting beyond the mandate would also undermine people’s trust in the central bank

At the end of the day, it could become more and more difficult for the ECB to focus on its promise of a stable currency