Maybe because it is over complicated ?
Many many cases to handle :
roms merged ? split ? unmerged ?
bios as well ?
and samples ?
chd in folder ? in zip ?
How to identify samples (they have no crc and no size) ? by their name ? confusing, or extension ? wav ? and now flc, mp3 and more ?
And identifying chd ? calculating sha-1 on the xGb files ? too long, getting it on the header ? which version ? v1 ? 2,3,4,5,... ?
Roms in a folder ? in nothing ? in a zip ? a 7z ? what next ?
Roms ? chd ? samples ? bios ? devices ? and next ? console ? computer ?
Main set or clone or bios or device or sample ?
What about roms inconsistencies ? Games with 5 times the same crc and different names ? merged roms not found in main set ? roms with Same crc in main and clone, but different names ? or same name with different crc?
How to identify roms with no crc ? sha-1? md5? or... ?
Moving roms ? from zip to 7z, zip to folder, folder to zip, folder to folder, zip to zip......
and more more more....
Good luck
