What are the benefits of this? over using any backend to build an api, generating swagger, open api, postman specs and then generating a client(s) in what ever language you’d like.

Code completion and variable type validation from the front end is nice.

Is there a direction this is going that differs from the existing tools?

The difference here is that this library is a one-line drop into your Python back-end to automatically generate the client.

Of course, the route you mentioned is much more powerful and complete, but here I'm trying to offer a way to very quickly build APIs without learning how to integrate any of those tools.