Microdoppler effect can detect the low frequency movement signature of the objects. So with the automotive radar we can detect pedestrians which are not in the line of sight of the driver. This is also helpful in the autonomous driving situation to detect different objects. The signature generated for humans, birds, propeller are all distinct from each other.
Microdoppler effect is also helpful in detecting defective parts such as ball-bearing in the machines which are not visible from outside as they generate different vibration signals which will be picked up by the RADAR.