Taking ideas from REST and putting it into your JSON-RPC API doesn't make your API REST. But you call it REST anyways.

It's like reading a book on building a house and using ideas to build a shed. Sure your shed has electricity and a sink but it's still a shed, not a house.

Same with terms like RESTful. You don't call your shed a "house like building" as it's missing key pieces of a house.

REST requires HATEOAS. The only real implementation is the world wide web. Everything else is really JSON-RPC or some other protocol with a few ideas borrowed from REST.