Why are HDD platters harder than the floppy/ZIP discs?

Hi:

I have a question just out of curiosity.

I notice with ZIP discs and floppies, the disc is a soft dark-brown
round film-like material that can easily be shredded -- with paper-
shredder -- to remove confidential information.

However, the magnetic platters in HDDs are much harder and metallic.

Why don't they make the hard-disc-drive platters soft like the discs
of floppies and ZIPs? It would be so much easier to remove unwanted
confidential information then. Simply unscrew the HDD, remove the soft
platters and dump them into a paper-shreder.

To remove personal info from an HDD requires that the platters be
heated beyond Curie point to eliminate all magnetic data. This is
extremely inconvenient and dangerous because of the high temperatures
required.


Thanks a bunch,

Green