I understand that Courtiers are members of the court; perhaps ministers, minor officials etc., but what do they actually do in CK2? I've seen various people's strategies involve filling their court with geniuses, or midas touched people, but why, and what for? I sometimes notice exiles entering my court, and obviously prominent vassal's families and the like, but is there actually any use to them? Is there anything more than just expanding your pool of candidates for the council slots?