What is actually different?
Both exist to solve the same problem: the phone rings while you are working, and an unanswered call is a lost job. They solve it very differently.
A human service gives you judgement. Someone who can tell an emergency from an enquiry, calm an upset customer, and recognise the client who has been with you for ten years.
AI answering gives you availability and economics. It answers at three in the morning, on Christmas Day, and on the twelfth simultaneous call, and the cost does not scale with how busy you get.
For most trades and appointment businesses, the majority of calls are routine — a booking, an availability question, a quote request. That is exactly where software is strong, and exactly where paying a person per call gets expensive.