I’ve been teaching a version for 2 years. Sometimes words keep people away. They tend to label a class. The term “fusion” also leaves room for instructors to include whatever they may find appropriate for the group. With Pilates, particularly, there are non-hardcore (for lack of a better word) people who love the abdominal/core work but also want/enjoy weight training and yoga stretches included in a class too. It just appeals to a larger group.