When I’ve considered JSON-RPC in the past, the lack of easily identifiable URLs was the main drawback in my mind due to the difficulty of testing and debugging—the same reason I would never use gRPC or similar on my own projects. That said, I think a well-made browser extension would fix this issue for most people, similar to GraphQL, but it still introduces friction that isn’t immediately beneficial. I’d still give it a try in the future!