But that is how we used to buy a plane ticket. Long before flights.google.com's price table, you'd call a human up and tell them you'd like to go on holiday. They'd ask you where and when and how much you could afford, and then after a while with the old system (SABRE) clicking and clacking they'd find you a good deal. After a few flights with that travel agent, they'd hey to know you and wouldn't have to ask so many questions.

Similarly, long before Waymo, you'd get into a taxi, and tell the human driver you're going to the airport, and they'd take you there. In fact, they'd get annoyed at you if you backseat drove, telling them how to use the blinker and how hard to brake and accelerate.

The thing about conversational interfaces is that we're used to them, because we (well, some of us) interface with other humans fairly regularly, and so it's a fairly baseline level skill to have to exist in the world today. There's a case to be made against them, but since everyone can be assumed to be conversational (though perhaps not in a given language), it's here to stay. Restaurants have menus that customers look at before using the conversation interface to get food, in order to guide the discussion, and that's had thousands of years to evolve, so it might be a local maxima, but it's a pretty good one.