Why run dual quads?

I was doing a little thinking-over-coffee this morning, and while perusing some threads where dual quads were a topic I came up with more questions than answers. In a nutshell, why would a person want to run dual quads instead of a single carb? For sure there is the coolness factor and visual appeal but otherwise what's the benefit? If running a pair of 600 CFM (or whatever size) carbs why not just run a big single 4-barrel?

Enquiring minds want to know...:)