There were mostly benefits: good organisation of the living room space, an opportunity to make the furniture exactly how we wanted it to look like and to fit into the exact dimentions of the room.
The only drawback is that the framework of the boockcases is fixed. I intended them to be shelf doors for additional storage. I think the manufacturers said that in that case, they could not keep the 45 angle trim at the corners. It had to be straight for the doors to open. So we dropped this idea.