Depending on how you make the game some launchers can make sense. You can set disolay options before launching the game. Back in ye olden times some games would launch by default in a set resolution which often made changing that in-game difficult as it would be off screen. Also makes your first time launching it a better experience than some low-res garbage. Also, without a platform like steam they can handle updates.

That being said, I don’t think most modern games need those functions. Graphics engines are pretty good at getting screen resolution from your os (not perfect). And platforms handle patches and updates.