It may have one value... To attract eye balls. Plus, we do need to illustrate our posts with something, even when we focus on text.
I agree that for a post focused on images or video, AI-generated images or videos are not the way to do it if you want upvotes. Of course, at some point, we might have issues making a difference. But by that point, maybe there will be some other AI tools capable of reliably telling AI-generating content from human creativity.
I agree that images do help to get attention and I see plenty of people use them when the post is a wall of text. I think that's okay. In the short form feeds you see a lot of generated images with no context.
I don't really follow the short form feeds unless I'm looking for something specific or something attracts my attention for a short while. They... wear me down.