It's only useful for the 'service' part if it can actually do stuff, and with the current state of LLMs it wouldn't be long before somebody argued such a service into giving them 200% refunds on everything and published the steps for everyone else to do the same.

From what I have seen from some tests at my company, you can almost always get hallucinations that are potentially very destructive.

But for front line "get this person to shut up and go away in frustration" customer service - not something for solving actual customer issues - it's a no-brainer.

I would guess that looping, no-human phone systems are just cheaper to keep for now.