Marie Kondo is famous because she had the opportunity, almost by accident, to show her book off. It was a hit and she was then able to luck into a show about organizing things. While some thnk the idea is goofy, much like they feel about Martha Stewart who did something similar with the older generation, some are captivated by the girl and by her organizational skills.
Today's generation has the need to be organized and to learn how to be minimalists to an extend. They are busy and mobile and when things are organized like Kondo teaches, keeping things tidy is much easier. Many like her style along with her knowldege. And then again, many do not.