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

I’ve heard (so no certainty), that they analyzed plastic trash collected from beaches and found plastic bottle caps to be a significant part of it. So they thought it would be worth trying to solve that problem.