Just about every frame will suit someone. Few are awful in themselves, hence the huge variety available. The point is, if you put a frame on the wrong person, it'll look wrong. But take it off and it'll look fine on another. Nothing to do with the frames, but the frame/person combination.
Also, do you ever see anyone wearing glasses on ads for anything else? I don't think so. See an ad with spectacles and that's what they're selling (unless you can find another one). Plus I've never seen one person on spectacle ads with lenses in the frames, so they all look like actors in a local amateur play, totally unconvincing and quite odd. If you're going to sell something, isn't it better to show it as it looks in reality?