The idea

Currently, when doing a raw download, (And presumably other formats that have internal file structures like CBZ) all image files are stored at most one folder deep.
The suggestion is to have the files in the form of [Volume number]/[Chapter Number]/[Images]

Why this feature should be added to the app ?

This is specifically to add compatibility to another app (https://github.com/ciromattia/kcc) to automatically split and add chapter numbers when converting to kindle format.