It's definately crazy
There is a cult in Japan (and to some extent in America as well) that is highly into Japanese anime from both an artistic and gaming perspective. It has tons of fans and for some strange reason, putting a "doe-eyed cutie" on to a product's box-art will increase sales. I can't put a finger on it, nor can any of my Japanese co-workers, but it is definitely a marketing campaign akin to putting an Apple lower case "i" in front of everything (iPhone, iPad, etc).
I play guitar as you know and I went to pick up an echo pedal from Japanese company Boss and it had one of those "girls" on the box. Why, I don't know. All I know is that someone in a boardroom in Tokyo has got it in to their head that the folk that follow that stuff will buy anything with that stuff on it.