Robin, you are right, of course the files are moved to ss_media. And this procedure does not limit the number of uploaded files.
I see two problems with renaming:
1. As mentioned in an other post, you might have thousands of files in one folder. If you ever have to work with one of those files on the server without knowing exact details of the file, it will be hard to find the file. I know, you will point once again to the media library, but I don’t see any reason why you should give up a meaningful file name, when the original file had this name at the time of import.
2. For SEO it would be helpful to have meaningful filenames