Yeah. We get "destroy it" requests from time to time. Easiest thing: Hit the drive with a hammer, and boy is that satisfying.
Of course, that was before these soldered drives. Hitting them with a hammer destroys the computer, too, so
That said, a 3-pass zero will make the drive unusable for all but the hardiest data retrieval, and a 7-pass puts it out of reach to everyone other than super-specialized equipment. In other words, you gotta have something on there really, really important for anyone—anywhere—to care!
It's time consuming and expensive, so the average Joe has little or nothing to worry about. You ain't got nothing they want.
If you
do have something they want, and are worried about them getting it, Apple has made it about as hard as can be on relatively inexpensive, consumer-facing hardware.
A person comes into the shop. They have File-vaulted their Mac. They have forgotten their password. They cannot provide proof of purchase. They. Are. Done. Data is gone; that's it; no recovery services here. And there isn't a specialist anywhere that is in their price range. Seriously, you
really have to have something they want.