[psychotik]

FWIW, I find it simple enough to add/remove codes as needed. I can see how punching ~15 buttons can be a pain, but I don't find it so.

[veemjeem]

I think the main benefit here is that it works with your existing lock, so it could work on apartments, dorm rooms, office doors, etc. Those key code deadlocks have always existed, but never very popular.

[khairulzaman]

In the US, maybe. Here in Seoul it's everywhere. Practically all apartment units come with them pre-installed.