With the reliance on card game imagery, other kinds of tabletop imagery would be splashed into pages where appropriate, for example, on the weekly events bulletin page, it makes more sense for this to be in the style of scribbled notes.
If you look closely, this is “scribbled” on the back of a Dungeons and Dragons character sheet, a common meme/joke in Dungeons and Dragons groups is that scheduling is a nightmare, so it’s a fun joke for those who get it, and a change of scenery which tells the viewer that the Dice Cup is more than card games.
Having hand written content also gives off a personal feel, while still feeling “designed”