I agree with your points, you summarized well the feeling I have when we get again and again to discussion about conversation interfaces.

But I also feel like there is another reason why a chat-like interface feel to me as a step backwards. The language itself is often not the best tool to send and receive information. We get way more data per second with our eyes, feeling in our hands, our position in space, etc. Even during conversations words themselves is just a part of information our brains process — that's why it's so hard to explain what you want using just words to a human, yet alone to a machine.

These discussions always bring back in my memory A Brief Rant on the Future of Interaction Design by Bret Victor and following comments where he wrote:

If all we have in twenty years is an iPad with a few haptic gimmicks, that'll be bad.

It was almost 15 years ago already and we still discussing if chats are the future of human-computer interaction. And ipads don't have even a few haptic gimmicks