I think CG artists being unionized will probably mostly hurt CG animated movies and Disney’s “live actors in greenscreen costumes on a greenscreen set that can’t even interact with eachother” genre. CG animation is currently full of movies done without care, which will become way less profitable, which is good. Disney’s treatment of live action actors needs to die yesterday, so that’s also good.
CGI has two upsides, however. The first is it can be used to enhance practical effects. I really like when this is done, it keeps the realism of practical effects and makes them fit seamlessly/able to do more. I suspect this is less time consuming than CGing an entire set, so it probably won’t go away, especially on high-budget movies.
The second upside is using cgi to add dangerous effects to movies (explosions, gunshots). It’s way safer to add muzzle flashes in post than shoot blanks, as proven on the set of Rust, and explosions are easy enough to film seperately and meld the images in post, or just CG the explosion with software. I don’t know if, with unionization, it will be cheaper for studios to use actual guns and explosions, and that’s the only possible downside (which is way less important than people making better wages).