is yuu a useless character?

Hello everyone, I'm a new Twisted Wonderland player, I'm currently on book 6 so consider this as a question from a relatively inexperienced person haha

While I was playing I was thinking how poorly developed Yuu's character is. Don't get me wrong, I love they and their interactions with Grim and the other characters but I can't help but feel that a lot of times (especially in the main story) they don't seem to make much of a difference in the resolution of the story, often left aside.

When I found out that the game's plot was about a person who suddenly finds himself in a world of magic while being an ordinary human without magic, I was really excited about how this would develop. It was a bit disappointing to realize that most of the time Yuu, as a character, not as a player, simply has no importance whatsoever. I feel like if they had simply discarded them and left only Grim, the result would have been the same. Especially considering that I came from the Obey Me game where MC had a lot of importance and development (despite the negative sides haha)

Anyway, these are just thoughts being developed, it's not a formed opinion so don't get mad :) I wanted to know what your opinion is, those of you who have been playing for longer. Do you feel this way too or is it just me? (English is not my first language, sorry for any speaking mistake)