It's easy to see why the additional sketches were not included before. They're not very good. It's also easy to see why they are included now. They're still pretty interesting even if they're not very good. The really interesting part, though, is comparing edited stories with restored versions: what was gained or lost or regained.
Usually both versions are good in different ways and it's hard to say which is better.
The Fragments included at the end are quite sad, showing Hemingway's repeated attempts to write an introduction to the book. (The previously published introduction was apparently fabricated by Mary Hemingway, his wife at the time.) Though each attempt contains some spark, all in the end fail miserably.
Though people persist in referring to A Moveable Feast as a memoir, Hemingway clearly considered it a work of fiction, saying: "All remembrance of things past is fiction."
Perhaps it should go without saying that memoir is simply a genre of fiction.