I think it would totally be useful!! It's a great idea with the size of these new f'n trucks!!
Here's some pics of it being useful!
^^Okay, but it's not like dropping the tailgate and sliding things over top to the bed is any harder....
Some of RAM's innovations, like the Rambox, their under-floor storage, and even rear coil springs (which facilitates air-suspension if you're into that stuff) is brilliant, and I totally get the appeal/utility of it. But this? I don't think so.
Maybe I'm a dinosaur, but I just don't see the point of the extra complexity.