I think every AI image/video that is strictly prompt → result without any kind of manual work or post-processing should go into the existing
AI thread. As someone who uses various AI tools on a daily basis, I consider stuff like this incredibly lazy and one of the main reasons why people have such an aversion for anything AI related.
People should only make individual threads for serious works that actually required some kind of effort (generating from your preexisting sketches; going through the image afterwards and retouching obvious AI mistakes; using AI only partially to generate assets for a photo collage because it's something very specific and you can't find a real photo reference; etc.)