Because it solves all sorts of other problems, like having a well-defined way to specify the schema of queries and results, and lots of tools built around that.

I would be surprised to see many (or any) GQL endpoints in systems with significant complexity and scale that allow completely arbitrary requests.

Probably for one of the reasons graphql was created in the first place - accomplish a set of fairly complex operations using one rather than a multitude of API calls. The set can be "everything" or it can be "this well-defined subset".

> I am wondering why you're using graphql if you are kneecapping it and restricting it to set queries.

Because you never want to expose unbounded unlimited dynamic queries in production. You do want a very small subset that you can monitor, debug, and optimize.