RR_NDB
i am trying to be objective, and generous. The SideStick is evocative of "A breed apart", and with "One Type Rating" family style, it certainly fits the bill. I am sad to say it is this concept (a breed apart), that sealed the design with sticks as far apart as possible.... To retain the Yoke retains the "look", and looks are important, so yes, it was a marketing tool.
Keep in mind, for better or worse, we see here in evidence all manner of "Defense of design". There is little if any of the advantages, not so apparent, are they?
Of the Bus Pilots I have interviewed, they speak highly of the airplanes' FBW. On the Stick I see mostly a shrug. It is as different, within reasonable limits, as it could be, the Stick thing.... Maybe to remind the pilot what he is driving?
Personally? I love the simplicity of the guts of the Stick arrangement, its lightweight (total add to gross) and its feel. It's solid. Placement? Not so much....
You ask the rationale, and I have to guess only. Gain? Also guessing, initial cost, (low), ongoing maintenance, (also easier and also low cost), and feather weight......
also 'Mac' (bear)