[konafocuswrc]

You are comparing apple to orange.

Dashcam is not an action cam like Ghost or Gopro.
Dashcam is a Blackbox.

It is always on, draws around 150mA. It has G-sensor and motion sensor.

When key is in and car is on, it is in driving mode. G-sensor is ON and when car gets hit, it records from 30 seconds before and after the impact.
When key is off, it is in parking mode. It relies on G-sensor and motion sensor. When someone approaches to your car, it records.

Blackbox is for your safety and evidence when you get involved in an accident.
-provides video evidence in the event of an accident.
-spot hit-and-run and theft, gets keyed.
-reduce your valuable time to settle a claim by the court or by the insurance company.