That would never work in a real fight because people don't just punch in like that.
You're right, people don't just punch in like they do in the dojo, but that's not the purpose of drills like that. They are used to familiarize yourself with the concept of a strike coming at you. It is used to teach you how to gage your distance, get you used to the feeling of blocking or redirecting, and place strikes in the proper, most effective places. So that if you do end up in a real street fight you won't be startled by a fist coming at you or the impact of a block or have to think about the most effective way to strike.









