This is a good use of an anthology chapter. Focusing on characters such as Frieda who has some significant impact early on, but gradually disappears from the story (or even mentions in the story) as it goes on. That said it makes sense based on the situation that it goes that way.
For those who hasn’t read the main story and curious (why are you here then), you can check the main story from the manga/LN from the shrine maiden and duke’s daughter arcs onwards. (Spoiler: it’s nothing serious, as per the title, the bookworm simply “ascends”)