My understanding is that IQ tests can measure a type of intelligence, but fixation on its narrow metrics can lead one to overlook other attributes that are just as likely to be relevant, but aren’t something that necessarily shows up in standardized tests. Add to that the fact that IQ tests can be heavily biased, and leave a lot of ambiguity for the proctors to interpret, it’s not a surprise that they’re so controversial.

I personally would be very suspicious if asked to sit for an IQ test as part of a job evaluation. I have worked for places that blindly worship context-free performance metrics, and it was insufferable.

IQ is a correlation variable that pops out when you measure any group of people's aptitude at a battery of tasks that involve thinking. Basically, if someone's good at one task that involves thinking (say, chess), they're more likely to be good at another task that involves thinking (say, reading comprehension). Apply some Bayesian statistics, and boom, you've concluded that there's some confounding variable (that we call IQ). Then you can start measuring how strongly certain tasks correlate with variable. Turns out abstract pattern recognition very strongly correlated with this unknown variable, so we can use that to predict what someone's IQ likely is.

The point is, due to the very definition of IQ, it's not a narrow metric, and selecting for it does tend to find you individuals who are going to be better than average at most anything. That said, it would seem alarming to me for a job to give me an IQ test instead of cutting out the correlation coefficient and just judging me on the task they're hiring me for.