The half step is one of those movements that some fighters do naturally and others HAVE to be taught.
A GREAT example of using the half step is the K.O. of Buster Douglas by Evander Holyfield to win the Heavyweight Title.
Holyfield used FOOTWORK FIRST to move back to the half step and then immediately attacked back with a half step in and a right hand that knocked Douglas out.
This understanding of footwork first and half step is massively important, not only for sports fighters, but also for self defense.
To know that you are in range and your opponent is not, is a great place to be in a fight!