So, Google, give us some insights!
All quipping aside, how useful are these sorts of features when it comes to trending topics? Honestly, I find the country and metro stuff the most interesting. This is very public information, so it's not like you have to be some crazy data miner to find this stuff out. It is cool to see what the interest is from place to place, though.
The trending searches are useful for knowing what topics to write about most if you're covering "The Force Awakens" hype. And it's good to know what the top characters and costumes are, as these are going to bring you the most traffic if you discuss these particular topics.
So I think these Google Trends features are cool, especially if you want to play some Twitter Trivia, or whatever it is these kids are playing these days.