In my case, the business did have human support assistants, but didn't do reservations via the phone. I had to switch to the web app for that, which was annoying (I was driving?). I guess doing user identification over the phone and scheduling the appointment are time-consuming for the human assistant, while these are some of the few things an app can do well. I presume the logic is to preserve human assistants for actually complicated or dynamic assistance, for the sake of cost-efficiency. A voice llm can bring down the cost of these basic-but-time-consuming interactions.