Currently working on a public-facing gRPC API and it's much more faffy than a REST API. Browsers don't talk gRPC which means you need to support gRPC-web endpoints. You probably need a gRPC aware proxy too and most of those have their own challenges. Some stuff doesn't like protobufs which means you need JSON transport which means protoc plugins. etc.etc. It's all just more work for (IMHO) little gain.