Window dressing ... pure and simple. And that's an observation based on a lot of Adversary time .... offered without prejudice or agenda, as you know I love my B/N's .... 
One adversary pilot came back alive because his RIO landed the TA-4J after pilot became incapacitated. He was more than window dressing and got an air medal for it (never had to pay for a drink as long as the pilot was around).
I beg to defer on window dressing as FFARP was a huge part of turnaround training and RIOs at VF-43 and VF-126 taught the appropriate lectures to squadrons (some pilot oriented "stuff" is better taught by pilots and same for RIOs). RIOs were also the GCI controllers at TACTS range that was fundamental to FFARP missions. Of course, I guess a pilot could do it, but I sure never saw one in the trailers (before they had nice building) except for debriefs. Another thing was RIOs were likely the ones to roll back to fleet as many pilots were using Adversary tour to springboard into the airlines (had the gouge book in the Ready Room).