I can't speak for every atheist, but in my experience it's the freedom to actually look at the world for what it is without having it shackled to bronze age mythology. The gift cards are just a bonus.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'
