[kenshaw]

There is an explanation in the README file, but I'll explain:

It helps to standardize workflows across a number of different source repositories (all Go based), where a number of different developers had come up with different ad-hoc ways of generating code against protobuf definitions. Since the syntax is Go-derived, it reduces cognitive load for developers when specifying protocol buffer definitions. We understand that it may not be for everyone, but it works for our team.

[grogenaut]

Why not just make a simple go tool that just covers that issue and still uses proto thus getting the tooling and expressiveness instead.