[derefr]

Protecting property is not the only use-case for locks.

There are also locks on e.g. cell doors in prisons. Those are pretty essential to the function of the cell, and tend to survive anything prisoners might try to do to them.

There are also locks (specifically, interlocks) on e.g. dam spillways, or on the airlocks on submarines. (For these, the "key" is a button somewhere else that's not necessarily itself secured, but it is still very crucial that they keep things out when that button has not been pushed.) They hold up pretty well—even against malicious infiltrators—mostly because they fail closed and have no UI components mechanically linked to the locking mechanism.