You're frustrating me. You replied to me saying "it's basically FUSE" and then after I replied to you, you come back and say, "it's not really FUSE."

Plan 9 supports file server processes natively, and that's the part that's most FUSE-like. The full OS also has many other worthwhile features that are not really addressed by FUSE on its own, or even by Linux taken as a whole.