Weather sealing on a garage door enables block drafts, rain, mud, and pests from coming into the distance beneath.

https://www.scribd.com/document/1053812878/Tornado-Preparation-Tips-for-Garage-Door-Motors-and-Openers-131240

Weather sealing on a storage door is helping block drafts, rain, airborne dirt and dust, and pests from entering the gap less than.