I feel like Illuna doesnt really have anything that makes them stand out, in a way the same applies to parts of Noctyx.
They honestly doesn't do anything interesting yet that made them stand-out. The closest that fit the idea of "trying to standout" is probably Scarle, whose stream tend to have a bit more handcams, along with her interaction with TEMPUS (Magni, specifically).
Regarding Nijisanji, I can somewhat understand why they never really talked alot in the thread nor discussions. While yes, they are quite a small blip on the radar where everyone and their mother either talk Holo or notable indies, I can hazard a guess that its probably because thanks to them being big in Japan but not exactly notable in EN (aside of their first few EN gen), most details that we could talk about are a bit hard to understood due to language barrier, lack of clips and other things.
The probably reason why some of us even knew about the Kuzuha cup thing was probably because most EN joined the cup, which is also the same with their latest Powerpro tourney thingie where the pre-selected coach from their NijiJP vtubers picking or getting EN vtubers and it resulted in uptick of fanarts and people discovering them, etc etc etc.
This could be me rambling honestly, but I think it's kinda clear if you realized it. There aren't any good content to justify the discussions, especially with the most clips focuses on EN than, iunno, the JP or ex-ID/KR and thus forcing folks to try and find something interesting while dealing with language they probably wont understand, and that with
so many vtubers on their belt, it can be a slog as well.