Have you never used a client library that provides its own API that wraps the web API? Something like Stripe, where you have domain objects and helper functions

Have you never used a client library that provides its own API that wraps the web API? Something like Stripe, where you have domain objects and helper functions and other incantations that are layered on top of the bare http? That's what the author is saying they don't have. When you import their client library you just have a new URI scheme you can use anywhere that accepts a URI, not layers of extra classes and methods to learn how to interact with.