seems unnecessary with encryption

ATA_REQUEST_THERMITE_RELEASE

ATA_POLL_THERMITE_RELEASED // always returns 0. Assume 1 if timeout

If smartphones can wipe themselves irrecoverably on factory reset by simply throwing away the storage encryption key, why not do the same thing and avoid all the trouble? Surely erasing 512 bits or so, irrecoverably, can be done quickly.

Flash chips, unlike hard drives, are highly reliant on their controllers. If you hit it with a hammer the data is unrecoverable. No need for a voltage zap.