I don't understand this comment. Of course the person mastering/editing the movie will have to know what they are doing. They need to ensure it's done properly. AI image generation is just a technique in the toolbox to achieve that.
That's not always practical, and sometimes even impossible for extreme slow motion shots. You aren't going to get cinema level quality out of a 5000FPS camera. For the same reason it's not a solution to say "just make every effect practical" instead of CGI.