I now understand what you meant.Try it yourself and see. A swipe involves a quick gentle movement and then the hand is just under the keypad. In fact even with short fingers you can pretty much keep your hand where it is and let your fingers do the walking.
With the current set up. The user has to physically press down the home button at the very bottom of the screen then raise your hand, move it up to the middle of the screen to enter the code.
The latter involves more movement.
But I think this is made primary for touch ID devices, indeed