I’ve published novels and non-fiction using word-perfect and, since publishers insist on it, Word. I’ve used Scrivener long enough to publish one fairly complex novel and multiple drafts of a unbearably complex one plus a non-fiction book in a Form I’m pretty much making up as I go.
Scrivener lets me (a) not lose anything (I’ve sometimes gone back to the very first draft of a book in the late stages of editing) (b) organize graphically any drafts, notes, corrections and research materials.
It soothes me to pretend that what I do is rational.
Customer support has sorted out my confusions politely and swiftly.
It’s a wonderful tool.