What IS a keypad lock?

A keypad lock is an item you can use to attach a code lock to a door or gate. The keypad is then just a bit of data taking care of locking and unlocking the door/gate it is attached to. A keypad is a functionality attached to a door.


What ISN'T a keypad lock?

The walls it places down, the gate or door


What are the walls for?

PZ desyncs moddata and/or door open state. The walls add another layer of protection so it is wise to enable the option

My garage door has some elements up, some down and it is all that damn keypad's fault

This issue happens even in vanilla single player games, so... hard pass on that. Inform yourself before accusing a mod for a core game issue.


The door is broken because the keypad is bugged

If the door you attached the keypad to has no tile properties for being indestructible, it can be destroyed by zombies or players (exception: see below).


What does the option for indestructible keypad related tiles do?

It makes the gate / door and the walls placed through the keypad locking process indestructible.


Why does this not work in tandem with vanilla door keys?

Because one of the mechanics it uses as a redundant way of locking is a vanilla door key id. Vanilla door keys and keypad locked doors are not supposed to coexist. It even generates the Key ID outside of vanilla key bounds to make sure. Imagine putting up a keypad lock only for somebody with a key to bypass it. Use the "unlock door" option like it is intended or don't use a keypad lock on that door.


I can still use "E" and other vanilla key bindings / actions to open a door

Yes, that happens and can't be reliably prevented. That is why there is an option to put up a tile wall as yet another redundancy layer.