Ratings given independently of reviews and anonymously are meaningless.
Most sites have moved away from allowing ratings on their own or allowing people who haven't bought / downloaded a game/asset to rate it. It's too easy for people to give 1 star or 5 stars and move on. When they need to write a review i.e. explain their rating, it becomes more meaningful because people can read the reason for their rating.
I've seen that itch.io still puts faith in ratings - especially when choosing games for bundles. But anyone can rate a game or asset - whether or not they've played / used it. I would encourage itch.io to rethink their system.