Why do people dip lobster in butter?

For starters, butter is nothing but fat. It gets in your ass and clogs up your heart. But that is not my question.
There are other sorts of sea food, that nobody would think of dipping in butter.
Who sticks a shrimp in butter? A scallop? A hunk of king salmon or a rainbow trout?
Why lobsters?
How did that practice get started.
Given the fact that most people do not want to get fat or have a heart attack, why does it continue?