Forgetting the paipan scene that I felt useless, the episode was fun because of the new interactions that new character brings.
And Gojou building a harem was a given from the OP for example.
You can also say he has godly sewing and tailoring skills seen from the perspective of those cosplayer girls, no wonder he attracts them with that.
Also, his hina doll nerdiness is not far from a cosplayer's nerdiness. Though slightly different, they can agree on the level of dedication and passion they put into what they like.