I think a lot of utadas success also stems from her looking normal. Japan loves normality. Of course her videos have strange themes and images, she herself is very average in appearance. She's not a super dolled up made up created image.
And also, she kind of revolutionized the Japanese music scene in a sense with the success of her r&b music.
__________________
"Remember, don't let others dictate your music taste. If you like whatever you're listening to, keep listening to it."