Just came across this article, which I think is worth reading, about James Frey of A Million Little Pieces fame - https://www.theguardian.com/books/2006/sep/15/usa.world.
This bit of the article stood out for me in particular:
To many, Frey and his novel were a big deal. Not just because he sold millions of books and was wept over by Oprah Winfrey, but because his was a tale of triumph over adversity, and it gave people hope. Frey still insists that the bulk of his book is true. His addiction is unquestioned. The root-canal surgery, queried by dental experts, is "true to my memory ... My memory is still what I wrote."
I think the triumph-over-adversity element will always be a bankable USP for memoir, but as with Frey’s memoir, this has come under scrutiny in TSP. The TSP revelations suggest so far that a large amount of the Walkers’ adversity was of their own making, and it’s much harder - if not impossible - to be sympathetic to that than adversity brought about by events out of our control.