I've been teaching, middle school and high school, for the past 15 years. I have always had a stash of chess sets and clocks in my room. They see pretty consistent use.
I love chess in schools for a number of reasons. One of the most interesting things about watching chess in schools is seeing who rises to the top. The best players tend not to be the brightest academic students. The best players tend to be smart kids who fight some of the bs that schools make kids endure. These kids are smart enough to 'get' chess, and have enough fight in them to stick out the difficult moments in games and tournaments that separate the best from the really good. These are the kids who tend to get in trouble a lot, who get bad reputations among teachers. Watching those kids show everyone up by winning chess tournaments soundly against the brightest academic kids is pretty awesome, and can be life-changing for some students.
I love teaching chess because you can teach anyone some simple ideas such as opening strategies, piece values, and simple endgames, and they can then beat anyone who hasn't learned those concepts. Kids who never thought they could learn a "smart person" game like chess suddenly play well, and start to realize they can do intellectual things. Then you start to see natural talent come into students' games.
Playing chess with kids is fun! If you have the chance, introduce a kid to chess.