Again, I don't think this specific example is hugely significant, I'm looking at the larger trend.
Re: public endpoints. Say you're poking around a public web service, and it doesn't provide an API. Maybe you're writing a browser extension. Would you rather reverse engineer a JSON HTTP API with no documentation, or a gRPC-Web API with no .proto file?
Re: public endpoints. Say you're poking around a public web service, and it doesn't provide an API. Maybe you're writing a browser extension. Would you rather reverse engineer a JSON HTTP API with no documentation, or a gRPC-Web API with no .proto file?