Why have a stainless steel griddle instead of simply a stainless steel pan? I've seen a lot of gas cooktops that have stainless steel griddles built into them. This seemed like a useful feature, but it occurred to me that I could just throw on a stainless steel pan, presumably to the same effect. 

Are there any advantages to having a stainless steel griddle like this vs. a good stainless steel pan?
A built-in griddle has much more area to work with, and is stationary relative to the cooktop, so wouldn't shift when you move food around on it.