I suspect it's less useful as a "this person will excel" test and more useful as a "this person won't fail miserably" test. Unfortunately the OP seems to be us

I suspect it's less useful as a "this person will excel" test and more useful as a "this person won't fail miserably" test. Unfortunately the OP seems to be using it in the former sense (when applied to the tries solution that he things will separate the "good" candidates from the plodding lunkheads).