Ask HN: Is the killer app for AR glasses a guardian angel to keep you alive?

Just like a smartwatch can save your life by monitoring your health (e.g., your heartbeat), maybe AR glasses can also save your life by monitoring your environment?

For example, AR glasses could stop you from crossing the street when there is an oncoming car, regardless of what the traffic lights indicate.

As another example, AR glasses could stop you from walking alone at night or passing through a high-crime area.