Earlier quoted context omitted.
A tenant who isn't able to operate a smartphone may also be unable to remember and/or physically enter a numeric code.
This is curious. The person is able to operate a key, but is unable to enter a physical code on a keypad? As for remembering the code, keeping a piece of paper with the code is no different from keeping a key. To clarify my position, I am not in favor of the app for privacy reasons, and prefer the physical lock and key. But it isn't clear to me how far the dexterity argument goes.
Even then, it's not equivalent: a hidden wireless camera installed by a thief can easily see the code on the paper or key thing, or even typed into the pad.