It means you can do pretty much “everything” from capture to delivery in it. Capture, editing, conform, compositing, title work, audio (up to a certain level), etc. At least that’s the theory, in practice for higher end stuff at least you wouldn’t want to do everything in a Smoke.
Most editing apps have pretty basic compositing tools (if you can call A over B compositing), no 3D environment, no paint, among many other things that most jobs require. So Smoke is indeed more than just a NLE.