I am not attempting to explain why every kind of food is selected for certain criteria for whatever reason. I am not also saying that you either select to for looks or nutrition. It's a matter of degree and compromise between different criteria. For quinoa particularly, I think it happens to be a type of food that largely guides people's preference based on nutrition rather than looks.
I expect quinoa will be selected for environmental tolerance first. Given how difficult it is to grow in th US, top priority would be getting consistent high yield in North American conditions. Breeding has to meet the farmer's needs before you start considering the consumer.
