I would agree with you except for one thing--it's very clear that's a second class citizen. There is this totally extra thing to support the original use case of etcd, and it comes with all the extraordinary quirks of how gRPC protobuf -> JSON serialization works (a strong term in my opinion).
It is very very hard for me to not see an unintentional conspiracy to push this very bad standard of gRPC. It does NOT make 99% of real-world programs faster. It does not make operations easier. It is not even a "data" format at all: go try changing an enum in downstream systems.
The standard is bad. Objectively, terribly bad. Someone somewhere on HN said that "Google was a ball-pit for gifted children." I kinda laughed at that, but really, after k8s and protobuf3, I won't even grant "gifted".
Google is a ball-pit for autistic children who can be funded by their monopoly on search. I'm tired of dealing with their protocols that make everything worse.