locks exist to prove unwanted entry more than they exist to prevent it. They prevent "casual" attackers as in they also prevent opportunistic attackers. They increase the level of premeditation necessary which in turn increases the risk for the attacker due to having much less of a sustainable defense.

ultimately, nearly everything can be destroyed in such a way as to gain whatever access to anything that you want.

A trustless society is a pipedream, but security theater creates an emphasis that limits plausible deniability. an attacker can no longer claim they targeted something they believed no one cared about, or that wasnt a big deal. For example, the level of theater involved in the TSA does not exist to catch every possible threat to aircraft. It exists so if anyone is dumb enough to smuggle a weapon through it and get caught then security can arguably gun them down on the spot. without the theater, the social contract is less obvious, and the plausible deniability for the attacker is stronger