Using rest api implies using JSON and GO as far as I know is pretty weak with it, so why companies still creating microservices on REST API rather than gRPC for example?
Yes, it is a good idea because JSON is text only. It is easy to debug and any programming language can generate and parse it.
Using JSON with GO is easy as long as JSON objects are simple and have a static structure. Things become complicate when JSON objects have variable content or contain a deep hierarchy of objects.
Learning a new concept, changing implementation, integration, tooling, debugging. We do communicate our internal microservices through REST-JSON, we do know RPC has benefits over REST, but for now, we don’t have big problems that could force us to migrate our infrastructure to RPC.