Why protobuf configuration?

[4nd3r5on]

Hi! I was researching the source code of this project and noticed that almost all the configuration is done with protobuf. I'm wondering why protobuf was chosen for this purpose and why don't just use simple Golang structures for configs? Are there some specific advantages for this solution, like easier to implement different configuration file formats support, easier to keep compatibility between versions, or is it making easier documenting configuration of the app?

UPD: Such solution has IMO major issue for code flexibility: you cannot give functions and different interfaces as a parameter without using any and then de referencing it. It makes harder to use patterns like dependency injection what is really bad. But at the same time it's way too time consuming to rewrite everything on simple golang structs without protobuf