You don’t find the storage space to be worth it? Everything in the back just gets thrown around and smaller stuff means more boxes.
I don't think you can see it well in the photo but I have a carpeted shelf on the other side of the bed, which is the same height as the bed.
It's perfect for smaller bags and other fragile trinkets and there's still storage underneath.
I found that I don't use the box very much, maybe just utilities, track boards, tools etc, stuff that always stays in the truck.
I think it would be more practical to have just a flap there, that way you can access the stuff that's in the back of the bed instead of having to crawl or hook it up. You could put a cooler back there and get to it from the side instead of clogging the space around the tail gate and having to shuffle cases.
It also frees the space inside the shell for larger items. My use is pretty specific, that's why it's cool that you can order the ARE shell with custom features.