I can see this being a slippery slope. Scrivener questions seem like they ought to be on-topic, at least to some extent. You know, "How do I do this specific writing-related thing in Scrivener?" On the other hand, what about Word? Notepad? Obviously Latex and tex go over on their own StackExchange. What about specific uses of version control software for writing?
And most of all, what about How to add a new section into a numbered list in MS Word? It seems off topic to me because I don't fancy this site becoming a home to all your Word or other word processing Q&A, but then again I can see questions on Scrivener and related software as potentially valid.