Even though he had the least amount of lines in LaLaLaLa (which received 3.5/5 stars according to IZM), he is so great because the work he made in that song helped it make a great, or, at the very least, a decent song.
He is one of the three singers who wrote some of the song (the other two being Changbin and Han).
I even made an event with his birthday on it!