For certain types of positions I think its a really great litmus test. It tests a applicant's personal discipline in coding as well as whether they have a pass

For certain types of positions I think its a really great litmus test. It tests a applicant's personal discipline in coding as well as whether they have a passion for the field outside of the standard 9-5. The largest issue with this is you can lose out on really good engineers who view technology as their work, but not their hobby. There is a great number of awesome engineers who only do work within their employment, and therefore won't have a good repository of code to show potential employers. A good alternative to this is to simply present a coding challenge to solve during an alloted time period (day/week).