Microphone network is mostly used for low speed and high noise Iranian Shahed drones which are also made from composite materials and have very low radar visibility. (For example, Moldovan military recently mentioned that they cannot detect them with their old USSR-made radars).

When one is flying towards you, you hear it from few kilometres away for minutes as it has very loud petrol-powered engine.

In contrast, when you hear low passing cruise missile, you will have just few seconds until it passes over you.