The original J sofa or J-lounge was designed to provide backrest while facing the front tv. Otherwise you have no back support while looking to the side and up to see the typical RV front tv. Made sense, but the hook of the J took up too much floor space in some floor plans (especially if no slides or only one front slide), so most of the J furniture got downsized until the hook of the J was just a vestige of its original intent. At best it provides a bit of a corner for a better pillow location. Then the length got shortened too, to provide more room for other floorplan features.
In it's present form, I don't find any value in it, but some folks still love it and won't buy without it. Different strokes for different folks...
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL