IQ also correlates with many other other things such as reaction time and other real, measurable phenomena, so to say 'yeah but that's just like, your opinion' is nonsense.
All things being equal IQ could have some value however, bearing in mind I'm simplifying here, not all things are equal. IQ is designed to quantify intelligence, not reaction time. Don't just go by the comments here, even mine. Look into the history of IQ tests, for what purpose they were designed, and what they really test for.