Weber grills aren’t cheap, mine cost over $1300, so they deserve protection.  Mine sits on a covered patio, but is still exposed to water and dirt, two things that can start corrosion.  This cover fits right because it was made specifically for my model.  It stays put in strong winds and breathes, important to prevent moisture build up.  I plan a long and useful relationship with my new grill, and this cover is a bit of insurance toward that.