Medical devices, subway car doors, severe weather warnings, heavy machinery, car alarms, software security alerts. They all notify you to indicate that something is wrong so that you can take action to prevent harm. Hospital monitors can detect a wide range of issues, from an incorrect dose of medication to an irregular heartbeat and beyond. They can quite literally save a life. The same goes for severe weather alerts that warn of impending tornadoes or hurricanes.
Every day we discover new vulnerabilities in our systems, cracks in the fence the adversaries take advantage of to get into your organization and wreak havoc. Understanding what you have in your environment (e.g., types of devices, systems equipment, etc.) is very important in order to make sure the controls in place are working and more importantly, keeping up with the threat landscape.