I'm with Nuliajuk here, you can certainly get by fine without standing out of the saddle, and some people just don't like it, but it does come in handy when cycling in city traffic, or anywhere else you need to rapidly accelerate. That's cool that she wants to learn.
Come to think of it, I probably rode regularly for almost a decade before switching to clipless pedals, trying a road bike or learning to ride no-hands. None of them essential skills, but I appreciate all of them now, for various reasons. I still struggle with getting a bottle out of a cage though, as I don't drink very often while riding. Should be working on that one!
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett