Game launchers track user activity within the game.

lol wut? I don't need to install a game launcher to track your activity in game.

If you leave a launcher running in the background at all times then you're sending at the very least your current IP whenever the client does a poll.

I also don't need to install a game launcher to do that, either. It's just a lot easier to avoid having my process killed if that prevents the user from having "social features" like a friends list and chat, the standard shit.