Let’s assume you are looking for one of your images that you know is somewhere in your image store, but you don’t have the original metadata. What if you can’t recreate in your mind the correct metadata tags with which to search for, and all you have is the original filename or a variant on it?
Or what about the times when you have 50 copies of the same scene & subject, that are similar but not identical, all have the same keywords, and you need the exact one?