The biggest problem is that they were making insinuations that it was intentionally similar to her role in the movie Her (and even contacted her directly to do it).
There are laws for unauthorized use of likeness that could possibly apply here.
There are laws for unauthorized use of likeness that could possibly apply here.
So they asked her and she turned them down. But guess what, they can get a pretty good result without even involving her. It turns out that her "talent" for the voice from the movie Her is in fact not so unique and valuable because it can be reasonably well replicated by other people, so why shouldn't a company be able to choose an alternative like that? A person should not have an exclusive claim to the rights of all voices that sound remotely like theirs.
The laws around this aren't strong (which is why her response pointed out the need for legislation), and as I mentioned OpenAI would have been in a much stronger position if they didn't directly reference the film publicly several times. One could argue that they were using the film and her role to promote their product.
Not to her.
Quite a difference.