[lukeschlather]

It's pretty fast to destroy all the keys in a TPM. Should take a minute if you know the right place to go. Meanwhile securely deleting a normal drive requires overwriting every sector with random data, which could take hours. So it also helps if you're giving away the whole machine.

[SoftTalker]

Smashing the disk with a hammer takes seconds. Or dropping it in a shredder.

Used disks are not worth hours of time to overwrite with random data. Just physically destroy them.

[DarkAtom]

Or a furnace. That usually leaves no trace of the physical disk having ever existed, which may be important for <insert state actor/military here>.

[minitech]

That’s wasteful, inconvenient, and not even necessarily unrecoverable.