Being able to have a great man to man defensive team means being able to do a lot of smaller things well. Whether it is being in the gap, communicating, being in the help, recovering on the pass, etc. You can't just jump into 5 on 5 man to man defense and expect it to be everything that it needs to be. That is why basketball drills like this 2 on 2 help and recover drill are so important to your team. They allow you to breakdown your defensive philosophy so that your players can get reps on specific skills that your defense is going to need to be successful.
Along with this being a great drill to work on defense, it is also great for competing and working on offensive skills. The offensive players are getting a lot out of this drill as well, and you can put a punishment on the losing team to turn up the intensity in practice.