I thought it was interesting because it showed the same clothes modelled by mannequins and, er, models. You can tell they're the same clothes, but they look far less flattering on the mannequins than on the models. That being the case, why have both? Wouldn't it put people off if they saw that the reality was worse than the ideal?
My guess is that no, it wouldn't put them off, because although the mannequins don't look as good as the models, people are more likely to identify with the models than they are the mannequins: "Yeah, they hang badly on the mannequins but they look pretty good on the models", something like that.
The fact that regular teenage girls don't look like models probably doesn't come into it. Well, except those that are models, obviously.