The aircraft is like a Faraday cage, it builds up static electricity that needs discharging to avoid noise & ensure a good quality of radio transmission, without interference.
Did you know : #A320 has 33 static dischargers of which at least 80% are required for correct operations.
Not all static dischargers are the same. Depending on their location; a straight mounting installed at trailing edges & a 30° angle mounting installed at tips.
If the a/c is struck by lightning, static dischargers are usually the first elements destroyed & can be replaced easily.
Author – Arjun Singh ( Airline Captain A320/B737)