It seems to me that people today are mostly rewarded for passing exams, not "IQ" tests. Being good at passing exams is different from being good at "IQ" tests,

It seems to me that people today are mostly rewarded for passing exams, not "IQ" tests. Being good at passing exams is different from being good at "IQ" tests, and neither of those things necessarily correlates well with being good at doing useful work. Provided that the candidates have had similar educational opportunities, I would guess that a traditional exam is a better measure of someone's ability to be good at useful work because preparing for an exam requires studying, which is a kind of work. On the other hand, if you have to compare candidates who have not had similar educational opportunities, something similar to an "IQ" test might be better, though you will end up selecting some people who turn out to be good at very little besides solving those kinds of puzzles, and who are perhaps lazy and disorganised to boot.