well it's literally just a tree of functions with extra metadata to make it extra powerful. Also have used both REST and GQL heavily and it essentially solves lots of problems I had with REST. I'm never writing REST again and when I see that something I'm consuming also have a GQL API it makes me so happy to be able to know every single field available to me.

The only use-case where it's annoying me is a CMS for building an entire site. It's recursive as A -> B -> A -> B and the lack of recursion as of yet makes it manual work to extract every level that you need.