In general I agree with the other comments that discuss that lack of sleep might have other issues so "work arounds" designed to help pilots and truckers probably aren't a good idea. However and in particular connection to this article there might be people who are at risk for Alzheimer's where it makes sense to "sweep" the brain more than once a day? So normal sleep + another process around 2pm? Not sure if it would work like that but that was what I wondered when reading this/
Some people have difficulty falling asleep, and other people have trouble staying asleep (often waking up really early in the morning). The latter is much more common amongst older people, even though the amount of sleep they "need" has not decreased -- they just have a hard time staying asleep for long periods of time. In that scenario (when falling asleep is not the hard part), a nap is probably a pretty good idea.
