There's this stigma towards AI in certain things that I find interesting. In your case was the weirdness (the uncanny valley area) due to the AI using Feynman's voice? Would it still be weird if it used a different voice?
The AI generation in this case is a tool to convert text to voice, one of the best use cases of this technology IMO
It was weird because it seemed authentic, but was not. There was nothing technically uncanny about it - the illusion was complete. Ten years ago I would have absolutely thought that it must have been Feynman's own voice.
I find it weird in the same way that I feel about AI services that will let you chat with deceased relatives. It's the principle of the thing that is unsettling. Perhaps future generations will find these objections quaint.