How to make a good use of WP Automatic?

Hey guys!
I've seen a couple of threads about WP Automatic plugin (to massively import articles from other websites).
I don't really understand how efficient it can be as all this duplicated content is negative for one's own website.
What am I missing with this sort of plugins?
How do you guys use it effectively to automate your blogs?

That is not about the auto post, i think some guys still make money with it, auto thoundsands of posts everyday. I code for myself plugin to auto post by keywords