I read it more as referring to the way the engineer approaches the problem vs what time of day they work.
An engineer who starts hacking away a solution and keeps at it 90+ hours a week (or whatever amount) but then because of this burns out and looses interest in 2,3 or 6 months is not as valuable as an engineer who can consistently keep working at something until the product is delivered. The engineer that is burned out probably won't be able to last X years at the company, and since the author is trying to somewhat maximize the time the employee stays the "burn-out approach" engineer is not desired.
Kind of like that other article that popped up in HN a few weeks ago that basically said "discipline over motivation", which I read as "it's better to be able to work 2-3 hours a days every day for 5 years, than being able to work 15+ hours a day for 3 weeks".
Obviously your opinion might vary as to how useful this strategy is, but I think it has a different meaning than just "an engineer that works at night".