Ditto. Here's another reason why you might want to do that. If people enjoy your game, you may wish to reach out to them to invite them as players on future projects. Having access to their profiles can give you an idea what their play preferences are. If you allowed people to Favorite anonymously, then you could overcome privacy concerns.

I completely agree with this, even if only the narrator of a story, or a user could see who had favorited them. Maybe even have the option for the one clicking the favorite button to say why they are doing it. Would be a great feeling to know that someone really enjoys your work.