A previous company used Real Colors, an MBTI knock-off, and it was striking how attached people got to those results. People openly stereotyped whole groups of people because they appeared to cluster in one sector (e.g., SDEs must be Green). They disregarded all counter-examples because they conflicted with these biases. It was weird.
People like boxes because it gives them an easy and reassuring way to approach complexity they are not equipped to grapple with. You see it all the time in the professional world: people who have to deal with others but are poorly trained and unconfident in their ability to handle human psychology relish these kinds of crutches. You see it even in this discussion: this type must be suited to this kind of job is simpler than thinking holistically about prerequisites.