the skill of an actor is that they can act out different personalities as needed for the film, but if they create a database of whatever personalities you can think of, you only need to find a person to have that personality scan them and add to the database.
so anyone can do this job for a day. acting skills are no longer needed, much less acting experience.
that means anyone needing a bit of money will be game to be exploited like this. basically we can expect that anything but major roles will be replaced if this is allowed to go through.
the actors guild will have to negotiate to somehow disallow or limit the use of AI generated characters. however if you want to create scenes with thousands of people (like the battle scenes in lord of the rings or the hobbit, which were embellished with the help of AI) disallowing AI characters would be too limiting