@eck89 and why not? It shows Nazarick's impact on the world and its day-to-day running. And I think Nfirea and his work become really important later on.
the author does a ton of world building and fleshing out the world besides just the nazarick bunch that's what makes this series so good. Its slower pace sure but it makes it so much better then something shallow that has little to no build up and all side characters are generics.
I used to look forward to this manga... back when the anime wasn't ahead of it. Now it's just "oh, another chapter, wonder how much longer until it catches up to the anime?"