So basically: it doesn't work well if you want to reach every IP on the whole internet. Yeah I suppose that's correct, but we are talking about internal service

So basically: it doesn't work well if you want to reach every IP on the whole internet. Yeah I suppose that's correct, but we are talking about internal service-to-service communication so why would you have those requirements in the first place? It's only call/response because that's all you ever need if you can call any arbitrary function by it's name. That's infinitely more powerful than any other protocol that restricts you to a limited grammar.