Why is the outside of grilled cheese buttered?

Question

Most grilled cheese recipes call for the outward faces of bread to be buttered, while the inside faces have the cheese inserted.

However, this tends to cause your hands to become very oily when eating them. What's the motivation behind buttering the outside, as opposed to the inside with the cheese?

Answer 1

The part that is buttered is the part that comes into contact with the cooking surface (a pan or a toastie maker). By adding fat the surface of the bread is fried rather than merely toasted, giving a different flavour and texture.