I bet they do the encryption like that so that you can quickly securely wipe them (just drop the encryption key) or easily add a password to the encryption late

I bet they do the encryption like that so that you can quickly securely wipe them (just drop the encryption key) or easily add a password to the encryption later (just encrypt the encryption key by a password). It's too bad if it's completely unusable without the enclosure, but that general technique is one that I'm a huge fan of.