Mind as well limit it to only games in your library than.
Plenty of other ways to play something than for you to physically hold it in you hands. Maybe the played it a vrcade, friends house, rented one, etc.
This would cause other problems too. People will mostly vote for more popular games because more people own them… Realistically I don’t think there’s a way to do this that would actually be meaningful. In general I’ve started to place an extreme amount of distrust in ratings for games and movies because realistically I don’t care what the average person thinks of a piece of media… I care what I think, and aggregate measures like that don’t really give you a good impression of that. It seems more useful to find good curators and people with similar tastes (or tastes you understand so you can say “oh they liked this, but I don’t like that kind of stuff as much as them” or “oh they didn’t like this, but that stuff is more my jam than theirs”.
