In short, it's used for automation of combat and crafting. Majority of authors do not provide methods of 100% AFKing for a variety of reasons; one being it brings too much attention to the community.
If your intentions are to "press a button", go away for a week, and come back level 80, that's not going to happen. However, if you want "assistance" in almost every area, there are lots of those available. DPS, healing, crafting, grouping, soloing, raiding etc.
Highly recommended that you read through the entire walkthrough where (I think before) you sign up also so you understand what you get (and what you don't).