While common opinion would say that any individual with a cognitive deficit (including the affective component) would be at a disadvantage at most complex (socially relevant) tasks, this is not necessarily true.
My personal experience is full of examples (like the fact that concrete thought enables you well for medical school). However, it is always nice to bump into some published evidence, like the advantage of brain-damaged investors.
On a wider perspective, predicting a system’s behavior approaching it as a black box can only guarantee an adequate predictive model if the number of observations is considered infinite. Otherwise, for practical purposes, some cases justify looking into its inner structure and workings, as it appears to be in the case of neuroeconomics.