How many times have you seen someone throw punches at the heavy bag or in shadows and they are not moving about as they throw?
They are not moving their head, their feet, their body. Not changing angles.
There are so many things they are not doing.
If you throw punches without moving off line.. then your opponent will eventually figure out where you are and hit you…. plain and simple.
If you move around without punching, your opponent will eventually figure that out too.. and just hit you.
Take the time to MOVE before, during and after your strikes.