Rosenberg has already killed too many teenagers for my taste for shock value, killing Hope... Meh.
Although yes, in his mind it would make sense. Especially with the directive that the X-men can not be old, I suppose they may want to get rid of Scott's granddaughter.
Even if I hate this, I'm probably hitting it and they're killing her so they can send the X-men back to the 90s even more.
PD: They can even make Wolverine angry by saying "That's why we can not take teenagers on missions" to reopen Schism's wounds and continue with the "Scott was wrong" narrative.
It makes a lot of sense.