Here's where the article goes wrong:
1. "Natural language is a data transfer mechanism"
2. "Data transfer mechanisms have two critical factors: speed and lossiness"
3. "Natural language has neither"
While a conversational interface does transfer information, its main qualities are what I always refer to as "blissfull ignorance" and "intelligent interpretation".
Blisfull ignorance allows the requester to state an objective while not being required to know or even be right in how to achieve it. It is the opposite of operational command. Do as I mean, not as I say.
"Intelligent Interpretation" allows the receiver the freedom to infer an intention in the communication rather than a command. It also allows for contextual interactions such as goal oriented partial clarification and elaboration.
The more capable of intelligent interpretation the request execution system is, the more appropriate a conversational interface will be.
Think of it as managing a team. If they are junior, inexperienced and not very bright, you will probably tend towards handholding, microtasking and micromanagement to get things done. If you have a team of senior, experienced and bright engineers, you can with a few words point out a desire and, trust them to ask for information when there is relevant ambiguity, and expect a good outcome without having to detail manage every minute of their days.