Heh, yeah, I've never been that big of a fan of LoL but it does everything really well for those who do enjoy that type of game.
In addition to the NPCs machine learning can be used to classify a player's play style, and with that analysis you can slightly tweak the gameplay to make it enjoyable to a wider audience. :)
Indeed.. Machine learning is another intriguing field. A friend of mine doing PhD in the same field, but I never got hang of it.. I guess I'm a slow learner.. :D :D