Technology

if you're using proper encryption it's going to be difficult or impossible to decrypt the files on the drive, so the data should be secure even if the drive is stolen, copied, etc.

Encryption should always be the last line of defence, encryption that is unbreakable today may be trivially broken tomorrow. Which is why I also I still prefer to overwrite drives with random data instead of just trusting the sanitise command (Even though I know that a big chunk of the data stays unoverwritten as part of the drive's "provisional area".

(Which raises another issue that "deleting" a luks keyslot or the whole header doesn't actually warranty it's deleted, may have just be moved to the provisional area. So if a key somehow is compromised it becomes nessesary to physically destroy the drive.)

However, when you're actively using the drive and have files decrypted, and then you lose physical access to your devices, you have a problem. IIRC that's how they got Ross Ulbricht's files - monitored him until he unlocked his laptop in a cafe and then grabbed it (and him). If you're worried about that specific threat profile it makes a little more sense to have an easily accessible physical DELETE EVERYTHING NOW button that only operates when the drive is running.

In that case I rather use something that will reboot the computer and shred the ram as it would serve the same purpose with the bonus that contents can't also be recovered from ram. Something like an usb drive with a string wrapped around the wrist.

Now, in the situation that the keys have leaked somehow, (like recording the keyboard from afar while the user types the passphrase) then the self-erasing hard drive makes a lot more sense, assuming the user has time to trigger the mechanism.

Now the issue is, that overwriting even a fast ssd takes time, so I'm assuming the device works by destroying or erasing a security chip that holds the keys for the main storage, however the data is still there if the adversary cuts the power before overwriting the whole drive. Ofc encrypted, but like I said before, encryption may be broken tomorrow. A physical or chemical solution that grinds or dissolves the chip somehow seems to me a better option, with the bonus that it can be made to work without electricity.