I have personally found it to be a practical, useful API standard that provides benefits over a JSON API in Rails. I wrote an article about some of the benefit

I have personally found it to be a practical, useful API standard that provides benefits over a JSON API in Rails. I wrote an article about some of the benefits a couple of years ago: https://0x2a.sh/from-rest-to-graphql-b4e95e94c26b https://0x2a.sh/from-rest-to-graphql-b4e95e94c26b. You can architect "traditional" Rails APIs to get some of the similar benefits, but GraphQL works out of the box with existing client libraries.