Why is it better - if it is better - to receive a story through multiple narrators? : Auster

If you can set aside the narcissism (why are the protagonists so devastatingly handsome, brilliant, precocious, successful?) and if you can suspend disbelief and accept that not only the author (main character) but the author's acquaintances all can and do write professional-quality narrative accounts of the epochal and traumatic events in their lives - and I can - the Paul Auster's "Invisible" is really good novel. I'm almost finished - just have Cecile (?)'s diary to read through, last 30 pages or so, and a lot does hinge on that diary, as there are many unanswered questions at least up to this point in this mysterious book. And probably not all will be answered, satisfactorily. Still, I tip my hat to Auster - the story is very engaging and full of possibilities and, as with the best of his work, he pushes us to think about the boundaries between fact and fiction, the fragility of the narrative voice, the problems of an unreliable narrator. For example, If this book is narrated by a 60ish Columbia-grad successful author, much like Auster, then who exactly is the narrator of the novel in progress, 1967 that he reveals to us? He says that he has changed all of the names, locations, etc., and so we wonder - what has he not changed? Is any of it "real," and what does it mean to be "real" within a work/world of fiction? Why is it better, if it is better, to receive a narrative through these prisms and fractures rather than just a straightforward story told by an older man reflecting on the choices he made in youth? It's better because that's Auster's material and his signature - he does not write about the world so much as about our perceptions of the world. He's a philosopher as much as a novelist; Auster is the avatar of the '60s fiction debates and discussions and wars about narrative invention and postmodern playfulness - we're of the same world and stock, though in my admittedly occasional writings I have turned by back on these fictive games and gone for more straightforward narration - interestingly (to me) covering a lot of the same ground Auster does but with a different narrative tack (we are from neighboring towns and only one degree of separation removed through various friends, though we've never met). Our writings are really different, but I admire his work, at its best, and will weigh in again when I finish Invisible.