If you take a "real" IQ test (see comments below), then the result is a strong statistical predictor of multiple future life outcomes - income, education level, health, even longevity. There are hundreds of studies that confirm these correlations. So in that sense, it "predicts" your future "success."
Performance is performance, whether it is a ballerina perfecting a pirouette, a pitcher throwing a flawless curve-ball, or an author devising the perfect prose. While narrowing focus within a particular field is required to gain expertise, looking across domains -- in this case, from intellect to athletics -- is useful to unlock novel performance insights.