Incidentally, Stephen King ended up actually putting that scene into one of his novels, the seventh book of the Dark Tower. This was fitting, I thought, since the idea of the Dark Tower is that it contains all worlds, real and fictional, including our own.
And counterproductive? King's approach to plotting is described as essentially thinking his characters into difficult situations and then figuring out the details of how they'll extricate themselves as he goes along. This works very well for Stephen King, but certainly isn't the only way successful authors approach plotting, and some of the meticulous planners are extremely good and successful writers too. It's people that don't have an innate flair for structuring novel length texts as they go along that are most likely to pick up books with titles like "on writing" though...
As an autobiography and homage to his passion, it's brief and very readable though.
Funny thing is, the two elements I remember the most from what I learned inside are at what could be considered both extreme of the "importance spectrum": double the s (the kids's toys) and don't write adjectives to give feelings and emotions when your task is to create them (if something is awesome, don't write "it's awesome", make it read/feel/look awesome).