No purpose what so ever in my opinion.
You can't have open while driving down the road... if you do, imagine the damage from a swinging gate.
Why the extra handle (afterthought) - with all the tech, they could just place another button in the "normal" release area to open that gate.
More shit to go wrong for no real purpose.
You have a tailgate step, use it and you can reach anywhere in the bed you'd like.
Looks like a left over bronco rear gate...
Just my 2¢