Kipping pull ups are often a movement that gets a bad reputation because it’s not a “real” pull up. In the sport of CrossFit they’re all about performing more work in a shorter amount of time. Whether you stick to doing “real” pull ups or kipping pull ups in a WOD, you’re going to get a lot more work done doing kipping pull ups in a much shorter amount of time.
However, it’s crucial to have the strength to do roughly 5 strict pull ups on your own without any assistance before you even learn a kipping pull up. Not being able to have the strength to support your own body weight can have long term consequences by learning a technical movement before a foundational movement in the pull up.
The beauty of kipping pull ups versus a strict pull up is that it not only works your arms and lats but you develop more abdominal stability and hip drive along with more body awareness. The hip drive in a kipping pull up transfers just like any Olympic Weightlifting movement when the timing in the hips are performed correctly to accelerate the barbell to the finish position or just like when you throw or kick a ball.
The Butterfly Pull ups are simply a speed and coordination movement that can be a little more stressful on the shoulder joints. Unfortunately, there are no transferable skills to this movement so this is movement should only be performed by the experienced athletes who have a desire to compete in the sport of CrossFit. I would highly suggest that if you want to learn the butterfly pull up you should consult with your coach first before attempting this movement.