these types of cookies may seem benign and helpful to users (and maybe they are), but i also wouldn't doubt that Google uses this information for persistent tracking.
it's already been disclosed that NSA uses Google PREF cookies to track users: http://www.washingtonpost.com/blogs/the-switch/wp/2013/12/10...
hence my other dispirited comment about the cookie UI... edit: reworded/clarified