I use protobuf at work all the time (not google) and prefer them over almost all other serialization formats. To be fair, I mainly work in Scala, C# and JavaScript where great implementations exist. In the case of Scala, IntelliJ just needs to know that the generated source files are just that and then it „just works“ for me
Well, REST is architecture. Protocol Buffers are (de/)serialization.
I've tried it before (& although it has the properties I like[language agnostic schema definition..]), it was finicky to get working with of one the biggest IDEs out there(IntelliJ IDEA)
Also, it doesn't support Kotlin yet.(Java interop only option)
The only place I can see Protocol Buffers being useful is inside Google..cos it was a pretty crappy dev experience.
And I would be pretty confident in saying that not many Googlers/ex-Googlers outside Google use it. Cos if they did, somebody would make the dev experience much much better.