What was shown in the anime-within-the-anime could be useful in a future episode for our characters. Our main cast has minimal screentime because this episode focuses on Kuku making a doujin out of the Uron Mirage characters. Dengeki Melon's real identity was revealed to her.
They may not have been the highest-effort OP and ED, but it's still pretty cool that they made an OP & ED just for the show the characters were watching in-universe.
Filler?
I skipped forward during the Uron Mirage thing, thinking CR mistakenly uploaded to the wrong anime. Then I saw they didn't but I didn't go back to watch it. Seems like I didn't need to either. 9 minutes was way unnecessary