As @Nikolaj_Selvik stated field aliasing is integral and the spec compliance has nested aliasing. Many tools/libraries for various language and frameworks are compliant with GraphQL specs which therefore makes them unable to work with MongoDB Realm GraphQL. Realm GraphQL is a great time saver but it would be much more useful if it was fully spec compliant.
If you desire further specifics - something like https://github.com/dillonkearns/elm-graphql is incapable of working with MongoDB Realm GraphQL because it utilizes nested field aliases when generating type-safe code for interacting with GraphQL schema. Dillon Kearns package uses GraphQL specification.
Spec compliance shouldn’t be a feature request, it should be available out the box to assure there aren’t unnecessary hinderances for anyone naturally expecting spec compliance. It would strengthen use cases.