Every vendor page lists what the product does well. Here is the other list, because the fastest way to a failed rollout is discovering these after you have built a process on top of them.
1 · Conversations that need real judgement
An agent can establish that a candidate has five years of experience. It cannot tell whether someone who interviewed poorly is actually excellent and nervous. It cannot read that a customer is upset about something other than what they are saying.
Automate the conversations where the information is the point. Keep the ones where the reading of the person is the point.
2 · Anything where being wrong is expensive
Models make confident mistakes. Most of the time that is a slightly odd sentence. Occasionally it is a quoted price that was never on offer, or an implied commitment.
The mitigations are real — constrain answers to a knowledge base, forbid negotiation, forbid promises — but they reduce the risk rather than removing it. If a single wrong statement on a single call is genuinely costly, that call needs a person.
3 · Bad audio
A phone call is already narrowband. Add a moving vehicle, a market, a weak signal, and transcription degrades quickly. The agent does not know it misheard, so it responds confidently to something that was never said.
This is the strongest argument for keypad menus wherever a single unambiguous answer is all you need — a DTMF tone survives conditions that defeat speech recognition entirely.
4 · Cold lists
Automated calling makes contacting people cheap. It does not make strangers want to talk to you. On a purchased list of people who never asked to hear from you, low connect rates and low qualification rates compound — and the volume you can now dial mostly buys you complaints and a damaged caller ID.
The technology amplifies whatever your list already was.
5 · Low volume
Writing a good prompt and a good rating rubric is roughly half a day. Below about a hundred calls a month, that setup cost never pays back and you would be better off dialling.
We would rather say this now than have you conclude it after a month.
What this leaves
High-volume, repetitive, outcome-driven calls where the information is the product and the list is people who expect to hear from you. Screening, qualification of inbound leads, reminders, confirmations, surveys.
That is a large and valuable category. It is not every phone call, and any vendor telling you otherwise is selling you a rollout that will disappoint.