I know this is a late reply, but gRPS is exactly the kind of RPC computer scientists talk about.
I'm not sure what you think RPC is but RPC is just the paradigm of calling functions on a remote machine, passing arguments in a structured way, and getting a response back. Which is exactly what gRPC, JsonRPC and others all do. As opposed to resource-centric paradigms like REST, query languages, and non-realtime paradigms.
The main gripes against RPC is tight coupling, lack of a discovery mechanism and caching out of the box, and difficult in error handling and session management. All of which are also issues with gRPC.
gRPC offers no real benefits or drawbacks compared to other RPC implementations except that it is built onto of Protobuf.