In the Ford case they hired an impersonator to sing one of her copyrighted songs, so it's clearly an impersonation.
In OpenAI's case the voice only sounds like her (although many disagree) but it isn't repeating some famous line of dialog from one of her movies etc, so you can't really definitively say it's impersonating SJ.
In OpenAI's case the voice only sounds like her (although many disagree) but it isn't repeating some famous line of dialog from one of her movies etc, so you can't really definitively say it's impersonating SJ.