Solve problems quicker and prevent problems too.
If there’s a problem somewhere, and only certain people have access to where the problem was, then you’ve just gotten that much closer to solving it.
Controlled access also prevents problems because, if access is limited, then responsibility is limited and, when responsibility is limited, people are more conscientious and less likely to make mistakes.
Turn public entrances into employee entrances. We had a facility do just that because people were freely entering a high traffic area frequented by heavy machinery.
That access system eliminated the chances of a costly accident. A small fob is easier to deal with than a big lawsuit.