It's just a language-specific variant of a 'Microsoft problem': you don't want the answer, you want to watch the process. It's similarly useful in theory. But in practice I think it has the same key failing: Performance is too skewed in interview situations for it to give you consistently useful insight into candidate fitness.

If you want to thin out a hundred otherwise-equivalent candidates - knock yourself out. But at that point you might as well be flipping coins.