She's not pretty, no, but she is striking. She has a lean look that is still soft and her harsh little face makes for an interesting contrast. I wouldn't call her a beauty, but she has presence. I think that sometimes fashion/marketing/modeling is about selling attainable chic. There are many women who are far from beautiful, and only hit pretty on a great day (given grooming, mood, and the right clothes). I think HHJ manages to carry a variety of looks and occasionally, at certain angles/poses, she conveys the erotic, the elegant, the erotic elegant, or the playful.
She doesn't in any way resemble the actress Han Hye-jin who is as cute as a button and pretty too.