My point being that what may seem aimed at casual readers may actually be useful and play-influencing material. Reading it I wouldn't consider play. (As I noted, I think Umbran's definition, while dictionary-consistent, misses the point of a game having rules... game play being activity influenced by the game's rules.)
I apply it to sport, as well. I don't consider my time stabbing a swinging ribbon or golf ball on a string to be fencing, but my time practicing with others is... even tho the gear is the same. The use of the rules of Fencing don't matter to the ribbon stabbing - even tho the stabbing the ribbon is a very good skill builder. Kicking a soccer ball at an empty net is skill building, but at a defended net is play.