Yes, SSDs set a portion of the disk aside for wear-leveling, so even writing zeroes to the entire disk from the OS does not guarantee that the data is completel

Yes, SSDs set a portion of the disk aside for wear-leveling, so even writing zeroes to the entire disk from the OS does not guarantee that the data is completely destroyed. (Similarly, hard disks may hold secret data in bad sectors.) However, this device has these capabilities baked into it at the firmware level, and the firmware can address individual cells. (Similarly, the controller can include a small amount of non-volatile securely-erasable memory for the key.)