In the equivalent REST API you would probably have to go far far out of your way to expose users order information in a reviews API, whereas in graphql that is the default.
In a typical REST application, it is enough to ask "does this user have permission to take this action".
In graphql, the question is rather different. It is "does this user have permission to access this data irrespective of the action they are taking", and you have to both ask that question and answer it correctly for everything in your graph.