How important is Fortitude?

I've been trying to get a Alice to fill out team. I had one for a long time, but her fortitude is just 80, which in my mind is dangerously low, as it doesn't take much for her to turn to dust. So I haven't been using her.

I finally got a second Alice... and you could probably guess her fortitude is also 80.

Is this as bad as I think? Or is she still worth sinking resources into?