I'll go a bit further than you here. My experience with using homework exercises in interviewing is that they provide a better signal of both technical ability

I'll go a bit further than you here. My experience with using homework exercises in interviewing is that they provide a better signal of both technical ability and technical level than anything else I've tried. Also, I work for the company which published the article under discussion here, and did the homework exercise when I interviewed there. It was refreshing to be given something that was an actual open-ended real-world problem, to be solved in real-world conditions.