TYPO3 Core

The ProcessedFiles Folder is flat and does not have any hierarchies.
If you have thousand images images which are displayed you have at least 2 processed images of it, several usages or a noraml image gallery you and up easily having up to ten processed variants of an image.

An large sites this creates a enormous amount of files within one folder, which slows down most filesystems, massively

If the driver supports subfolders (is a hierachical storage), the storage should organize processed files more intelligent within the processing folder.