It teaches you that you can survive stressful situations. That you can handle fucking up and be yelled at/disciplined for that fuck up. It better prepares you to own up to your mistakes in the future because you've made mistakes before and survived the fallout.

Or that sometimes bad shit just happens and you get yelled at/disciplined for doing nothing wrong at all or because your buddy did something wrong and that's okay because you'll still make it through. That it doesn't reflect on your inherent worth as a person.

It teaches you to pay closer attention to what you are doing and be more mindful of not screwing up because the consequences will be right in your face. More often than not there are other trainees around who can witness what will happen to them if they fuck up so it's also a training exercise for anyone around to witness it.

Outside of this gif it also teaches you that these same DIs that are screaming at him might be seemingly angry at him now, but they aren't doing it because they dislike him, they dislike whatever he's done to cause this to happen. They will be cheering on his successes in the same way they are furious with his failures.