I have a 100$ big light basket from Cabella's. I used it often on my OB due to lack of interior cargo room. It was very useful to place an inflatable boat there, for example. Normally, it held a couple of boxes, TRed 1100, kids' sleds, things like that. I really used it with the Outback.
So by default I mounted it on the 4R on big trips early on. It barely carried anything. I have not used it in 2 years. It drops the mpg by like 2, which impact the range, which matters in the SW (I don't carry extra fuel). Its best use on the 4R was as a roof skid plate in Montana, not kidding.
I find that nowadays I normally go at a good pace through the desert or when in low range, I am often off-camber or on narrow, awkward spots. In neither of those scenarios I care for anything on the roof.
Remote camping...is for younger folks LOL.
So unless you are camping remotely for more than a couple of nights, there is no point. And I would by no means sacrifice my pace in order to carry stuff. My weight is really concentrated in skids, sliders, and LTE tires. I am very light on top. But that's me. It is all personal preference.