Bench while laying on ground

What does laying on the ground and benching different from a normal bench?

There is no sticking point when on the ground. Because the arms cannot go behind the shoulder girdle and do not allow a full stretch into the pecs you only push through half the movement. This is an example of the overload principle because it allows you to pus more weight because the range of motion decreases. BUT you must not use this technique all of the time. It is important to allow the muscle to be worked within a full range of motion for proper development of that muscle group. Using an exercise like this or partial rep training allows and can help you push and break through plateaus you hit. I would supplement this into your program but not make it a habitual movement that replaces jumping on the bench