I guess the part I'm missing, then, is where the author implies that the resulting document is "good prose". One could read such an implication into what's been written here, I suppose. But to me I read more that this technique is just about a producing something useful, not necessarily good (if by "good" we mean "equal in quality to what a skilled writer would have produced after many hours of deep thought").

Not every email we send needs to win a Pulitzer prize, after all.