Boxing is a good sports person keep fit if he is doing boxing, I suggest to everyone to train for it.
Boxing is not for everyone. I don't say that to be rude but it is not like many other martial arts. Boxing requires a certain endurance mindset that's found in certain sports like wrestling and long distance running, both of which by their nature will exclude all but the highly disciplined. People who boxercise get, in my opinion, partway there because pure physical exercise of any intensity is bound to hit a person's limits at some point. But to be frank, most people don't handle pain well, and boxing is painful. So much so that when boxers watch a boxing movie (I watched Creed again last night) we actually feel the movie in multiple ways, a lot more than most people who mostly feel inspiration and maybe some courage. These same people then join boxing clubs and quit after one lesson because they don't want the hurt. Boxing is part inspiration, part acceptance of getting hurt. And it's a long shot from the "no pain, no gain" principle, you have to want to get hit in the face, know it will happen, and when it does pretend as if it didn't even matter. My personal experience is most people can't do this their whole lives, unless they are lucky or they have great teachers.