i dont do crucible because it is always laggy and has become just a shotgun, single person super, fusion rifle, fest. and with most of the halo games the custom games never counted towards actual commondations or medals or anything like that, it was always just a way to BS with some friends, at least in pvp matches you and your friends can actually play against real enemies instead of eachother and actually get rewards. i remember seeing on halo 3 it would say 20,000 matchmaking kills 30,000 custom game kills. the only reason to have a custom game would be to try to learn a map and find good positioning or hiding spots or choke points, if you are running around the same maps battling your same couple of friends its really just wasting your time especially if you have similar playstyles.