Why do pirates expect people to download ARCs of books on their sites instead of paying for the final version?

ARCs stands for “Advanced Reader Copy”. Though it’s not always the case, sometimes they are retail. But I don’t see any advantage in downloading a book which is not even its final version. It’s a trend to upload it where it’s not even good for the nerds. I think it helps them avoid legal issues with the site, so as not to be seized. Also, to gather more people to their sites. Also, to encourage them to buy the real books. So, in a sense, it works. Anyway, I’ve said what I know.