I watched a great video the other day with ai voice, but the creator had a disclaimer at the start saying (in his natural voice) that he thought his accent was too strong for people.
All the comments (barring a few chuds) were people encouraging him to just use his natural voice as it was perfectly understandable and the AI voice was quite jarring in comparison.
So yeah even as an accessibility tool, I think people just find natural voices more trustworthy.
L'Nux