@nprofile1q... although intelligence is far too nuanced and multifaceted to be captured in a number, it does unfortunately have a statistically significant capability to predict likelyhood of some outcomes.
the more important question is "what do we do with this?", which I think is the point where prejudice and hatred start abusing a useful metric.
I think we shouldn't write off IQ because it can be useful in specific contexts; for example, showing the effect of reducing iodine deficiency :D
having said that, I do agree with the underlying sentiment that we should stop linking people's worth to their productivity under capitalism