Japan provides ample evidence of what happens to savers when the central bank holds down rates hoping for higher inflation. All Japan did was accumulate debt. Inflation went nowhere.
What good does it do to set a target when you struggle for decades in the case of Japan and one decade in the case of the ECB to hit your target? Fundamentally, these are not even the correct question, but they do highlight the silliness of the discussion which is asinine on many levels.