Best practice is to redirect all attachment posts to the main URL anyway. That’s why Yoast offers it as an option. It’s what anyone with basic SEO knowledge does.
SEO has nothing to with this.
For each image uploaded via the media library wordpress create 1 post in the wp_post database table (type:attachment) for each size you have in nedia settings.
In the worst case scenario, it creates 1 post for the original img, 1 for the large, 1 for the medium, 1 for the small and 1 for the thumbnail size.
If you have a directory with 1000 listings each with 4 images. In the wp_post table of your database you will have 20k posts that you shouldn’t have.
20k useless posts stored on your datbase, just to be able to re-use images instead of re-uploading them isn’t a good idea, otherwise we would have done it in the 1st place.
Thank you