The problem
Devices keep getting thinner, and a magnet small enough to fit is often too weak to be useful. Making a conventional magnet smaller makes it weaker. Strong conventional magnets also spread their field, which can disturb a compass or magnetometer and wipe the stripe on a credit card sitting near the device.
Accessories add a second problem: they need to land in the right place and orientation every time, and come off easily when the user wants them off.
How coded magnets help
Correlated Magnetics Research says Polymagnets concentrate force near the surface, raising strength up to 5 times, so a small magnet can hold well. The same concentration limits stray field, and CMR says its parts are designed not to interfere with sensitive electronics or damage credit cards.
Patterns also add behavior. Align pairs locate a tablet in portrait or landscape; twist-release pairs let a phone come off with a turn; spring and latch pairs set the feel of a keyboard snapping on. CMR lists tablet cover attachments, smartphone peripherals and magnetically attached power and data cords as uses. A LAPTOP Mag article reposted on CMR's blog said Polymagnets were used in detachable 2-in-1 laptops, and CMR has presented a precision-alignment case study on Polymagnets for iPad peripherals.