An ultra-loose monetary policy is a course of treatment with risks and side effects. For that reason, it must not become a long-term therapy, especially as its positive effects decrease the longer the treatment continues, while the risks increase.
There is a danger of economic agents ̶ such as households and, in particular, enterprises, but policymakers, too ̶ getting used to the ultra-loose monetary policy. Eventually, this might mean that a necessary structural change fails to take place or that enterprises without a sustainable business model are kept alive.