A lot of online games seem to use separate application for a game lobby where you log into your game account, pick a server and then launch the game. This is also where downloading patches takes place.
I'd like to know, what are arguments for using lobby as a separate app, rather than build it into the game? I mean, it could do the same things, but as a game. This often has a side effect in some games, that forces player to quit the game if he looses connection, because reconnecting is only available through lobby.
Are there some serious things to consider if I'd like to integrate game and lobby so its one process, that can restart itself if executable has to be patched?