Later I read another book, Made To Stick, that kind of cemented this belief. That too is a great book, full of interesting little insights, and I'd highly recommend it. Stories, especially the simple kind that can hook our attention, are far more effective than facts alone can ever be.
Of course, if you have a real life story that meets the criteria of being interesting and contains all of the lessons you need it to contain, that would work every bit as well as a fictional story (maybe even more so, thanks to the true-story element). But real life doesn't often work out that way. Things aren't so neatly laid out, and you need to be careful not to get lost in the minutia. I think writing from a fictional perspective also helps you to focus on what parts of the story are truly important to what you are trying to say.
As a final, and tangentially related note, I think this crosses over to technical writing too. The best technical book I've read (and over the years I've read quite a few) is Agile Web Development With Ruby On Rails. I think it's down to the way there's almost a story there, with the web shop that they're building in the first half of the book. That makes the book interesting. I raced through that section. The second half has no narrative, it's just a bunch of technical facts laid out -- I don't remember anything from those chapters. No other technical book has made a lasting impression on me like that, and I strongly suspect it is because none of the other books have had any semblance of story or narrative.