It is the easy way out when the European Central Bank is always on the buy side of the bonds. Issue more bonds. That dynamic changes when ECB reduces the bond buying (maybe from September but certainly in 2019). I doubt the politicians have worked that out yet.
The weird part is December 2020 interest rates are now back to zero. I cannot see that as being sustainable while the rest of the world raises rates. If the ECB is no longer buying bonds, there will be no other buyers of European bonds other than European pension funds and life insurance companies who are required to buy. I guess they can just tell them to hold more - done that in the past.