My girlfriend converted from snowboarding to skiing this year, and the first few days were rough, but ten days later she's 50-50ing boxes and skiing green runs switch. In the park, she doesn't hit any large features, but she's fast enough to not really slow me down, and if I'm skiing backcountry she just skis groomers with her snowboarder friends. And she likes ski movies now. Definite win.
I guess it depends on the person. If she really really wants to learn to ski, it'll be good. If she only kinda wants to learn to ski, it might be really really bad.