I think the Sultan had a bit of musing on this a while back. Might as well share it, or at least the parts which don't say much about the context.
His Magnificence Sultan Shahryar, Favored of the Titans wrote:Courtly games came so naturally to even the practical sort of courtier. Sultan Shahryar could see in them the seed of something useful- for a prosperous side with many commanders jockeying for position, where displayed cunning could lead some to rise to prominence and thus benefit the side more. They were even a form of training, for those who might be called upon as ambassadors and have need of a background that let them turn one side against another on the strength of their words and implications.
Basically, courtiers are naturally given to scheming and often-vicious social conflict because that sort of personality is more likely to produce a stronger side overall than if the side's courtiers are all unimaginative, unified, and selflessly loyal. Those personality traits are for infantry. Courtiers are popped for nasty social wars full of backstabbing and maneuver and have personalities to match.
...or maybe that's just my courtiers. I love them anyway; they're good units. Will pop more when I can.