I would argue it's an Amazon referral engine framing itself as a book review site. They have optimized for purchases and not for reader happiness / quality.

A competing site that is focused on surfacing books that the reader likes, with links to more than just a single purchase point would likely gain enough traction to be useful.

I imagine that scraping a user's GoodReads profile every now and again with authorization would also allow the user to update status in their Kindle / eReader while still populating another site, which would be interesting.