I don't think she'll be irrelevant towards the end of the story because I think her story interweaves with the WG storyline in a lot of ways. Who her real father is, how they did genetic experiments in the WG, the fact she's basically a proto-Joyboy.
But she is still just a kid, and a kid that was Bubble Boy'd for the first decade of her life to boot. So what she can provide to the story in the interim is close to nothing. Not good for exposition, too young and dumb for gameplanning, kind of a liability outside of being another helping hand in a battle. So she might be shelved for a while. Curious as to where she ends up post-Elbaf if she departs from the SHs, probably with Vegapunk.