I'm not convinced. Often the productive "hard worker" persona tends to push through tedious manual tasks, where the unproductive "lazy" persona gets bored and looks for better ways to do things.
The lazy persona risks not understanding the problem well enough to come up with useful solutions.
You need repeated exposure to the problem in order to see patterns and to find a good solution.
I agree that it's good to take a step back from time to time but IMO it doesn't make sense to think about productivity in a generic way (e.g. in terms of time management). Even the author admits that "getting in the flow" is important. The flow is everything. My point is that you should make your entire life about "the flow".
