If you want a tool to be able to generate executable validation from a schema, a compiler framework should come in handy.
It seems like they did not aim to make yet another mvp configuration language, but something that can scale across a wide range of usage scenarios spanning all the way from short-lived processes reading a number from a file to huge libraries of default/override hierarchies. Lack of universality sets an upper bound for the value of a configuration language, particularly when seen through the lens of configuring heterogeneous tech stacks.
It seems like they did not aim to make yet another mvp configuration language, but something that can scale across a wide range of usage scenarios spanning all the way from short-lived processes reading a number from a file to huge libraries of default/override hierarchies. Lack of universality sets an upper bound for the value of a configuration language, particularly when seen through the lens of configuring heterogeneous tech stacks.