Idk if this is “a reason” but leaving the launcher running without actually playing the game does count as playtime for steam, which may result in folks not being able to refund it if they don’t like it, and increases overall hours played.
Whether that’s part of why these games have useless launchers, or whether those things actually pan out that way, who knows.
16gb and a number less than 16gb both not being big enough numbers is making me crack up