Holy shit noa is fucking useless, the only thing she does is get status effects
she gets stronger as you unlock more scenes with her. Try taking her all the way to a rest zone while she has a status, you'll get special scenes and buff her stats.
For example, the first time you take her to a rest zone while paralyzed, you'll learn how to cure paralysis in combat. The second time, you'll get a scene and +1 to a stat. You might have to progress further in the dungeon/story to unlock some of the later scenes though. Try taking her to rest zones with various statuses after clearing floor 15.
I'm at floor 25 and she does like 7 with all her abilities, I could probably get her to 9 if I really go for all the scenes.