There are obviously cases where CUIs work well: while driving if you don’t have a physical button to do the thing you want, the CUI is better than a screen UI, and if it’s a complex thing, you would never have a physical button for it anyways. In the home when you want to control devices in the morning “open all the shades” or “open the north shades”, unlock the door and start the car, etc…

Not really conversations though, more like accessible commands. I don’t think we get conversations until the tech improves and the latency goes way down, meaning on device processing of speech at the very least.