Some voices are sexy and both of them fall into that category -- but that's beside the point.
That aside, it is genuinely pleasant to have a conversation with chatGPTo and some of that has to do with the voices. There's a kind of irony here because people generally imagined that AI would be cold, logical, unempathetic, etc. But LLMs are the opposite; they're extremely polite and deferential. Meanwhile they aren't that good at logic!