1. Ceramic interior keeps salt from retaining moisture in steamy kitchens or humid climates down south
2. The large opening is to access salt while cooking
3. Keeps debris from falling into the salt. The side opening keeps debris from settling as it does when salt is in an open bowl.
"Most people seem to say that the opening resembles the snout of a pig & that's where the name came from. However an old Scottish definition of "pig" is a jar or pot made of earthenware."
Apparently, I love all things Scottish even when I have no idea that they are Scottish.
information taken from http://chowhound.chow.com/topics/358131
