I have to respectfully disagree. Granted, writing about oneself does take a certain finesse and if done poorly, doesn't play well, but my most successful pieces have been about me and my life. I've won challenges, including some pretty good coin, on those stories, and they have been among my best performing works. I'd go so far as to say, most of my poetry, which gains decent readership, is, in some way or another, based on my life. I think the key to writing about oneself is to make it relatable, of some value to the reader and to grab their emotion through a familiar feeling or experience. I wouldn't be so quick to discount it, if it's done properly.