Evidently, the brand must have decided that marketing-wise it pays to capitalize on her persona. In the past, she was the face for the Private collection flankers (which, after all, were supposed to be "private"). Perhaps sister Jane is not equally photo-ready.
If I'm not mixing up brothers, the father is the collector of German and Austrian art who created the Neue Galerie.
The reviews I've seen are rather uninspiring. These are not classic, ballsy, confident Estee Lauders.