I would say that OpenAI wanted something that sounded like her which in turn sounded like Scarlett Johannson.

I also think the "sounded like" is less clear than you think. Is it similar, yes. But how similar I am not sure what the line is but for sure I didn't think it was Scarlett Johannson. By saying it is Scarlett Johannson and relating it to her our brains will make the association though. That is marketing.