That really is all the MBTI does. I know I'm an introvert and the the test told me that. What it did for me is tell me some things that I knew but didn't understand well. I think the perfect use for it is to take all the extroverts and put them in a bullpen, and put all the introverts in offices. That bullpen (for collaboration) versus office (for concentration) controversy continues all over the industry. Some believing that productivity will improve if we do one or the other for all employees. The reality is that each floorplan format works well for some people and terribly for others. Some people are infatuated with one language, while others will program in any language you throw at them. It doesn't mean that one developer is better than the other, it just means that if you or your lead understands that, you can be more productive by choosing the projects wisely with reference to your ability, personality, preferences or any other knowledge that might be applicable. And conversely, if a manager doesn't consider those things, he (generic term for all people) can adversely affect productivity by putting the wrong people together or assigning the wrong project to a person, etc.
SS => Qualified in Submarines "We sleep soundly in our beds because rough men stand ready in the night to visit violence on those who would do us harm". Winston Churchill "Real programmers can write FORTRAN in any language". Unknown