It does host comp stomp games, but it's random. It will randomly host either an Old GOW EF game, or a GOW BNE Compstomp game. It's a 50/50 chance. You can tell it to host a compstomp directly as well by using it's commands.
Most people use it to assist in hosting their own games using the enter/leave trick. Basically if a group of players wants to play, but no one can host, they can all enter the game hosted by the bot, then they all leave, someone hosts, and then they can all magically join. That seems to be what most of the vet players use the bot for. The new players will use it because its probably the only game that they dont get kicked from. So it's useful to both old and new players alike.