"When a measure becomes a target, it ceases to be a good measure."[1] These coding challenges used to be a very good measure of ability, but now applicants are just memorizing the most common problems for each company. We're not at the point where these tests are useless but we will get there in the near future. The problem is that I haven't seen any good alternatives. [1] https://en.wikipedia.org/wiki/Goodhart%27s_l…
The same can be said for the SAT. Unfortunately there seems to be significant enough overlap between "good test taker" (or in this case "good interviewee") and "good worker".
SAT is basically an IQ test, which is of course a reasonably strong predictor of white collar job performance (ceterus paribus).