I could also imagine DRM, though not directly privacy related, being a thing. Like the issues of freedom and openness are probably also important to many people who value privacy and might therefore prefer GOG or something over Steam.
Edit: I see someone else mentioned this already: https://lemmy.world/comment/16903223
Congrats! I’m glad I never started using it, cause while it hasn’t been easy I think it’s likely much harder to get off of it. So good job!