I can see right now that you will write anything for the sake of argument, whether it makes sense or not. I talk boxing, not bs so I am done with this.
It's a punching motion and its typically above he head so it should provide some exercising of the muscles to keep ones hands up. It works as much as weight lifting or doing sit ups. It is exercise so I don't see what the problem is. What type of exercise apart from boxing do you think helps with boxing?