A wearable can report a spike in heart rate for a dozen harmless reasons — exertion, heat, a steep climb. The value of a predictive safety system is in separating that noise from an actual early warning sign, without so many false alarms that operators start ignoring the dashboard altogether.
We spend as much effort tuning that signal-to-decision layer as we do on sensor hardware. A command dashboard is only useful if the people watching it trust what it's telling them — and that trust is earned through accuracy, not through more data points.