As someone who's daily job is to move protobuf messages around, I don't think protobuf is a good example to support your point :-)

AFAIKT, binary format of a protobuf message is strictly to provide a strong forward/backward compatibility guarantee. If it's not for that, the text proto format and even the jaon format are both versatile, and commonly used as configuration language (i.e. when humans need to interact with the file).