Why is the menu important to an establishment?

Question

Why is the menu important to an establishment?

Answer 1

I thought the answer was pretty obvious.  It's where an establishment makes their money!  If you have a crappy menu, poorly designed, serving rubbish grub at extortionate prices, then no-one in their right mind is going to want to eat there!  Enough said.

Answer 2

some of the best places i have eaten at have their menus on a dry erase board above the register

Answer 3

It's often a diner's first impression of the quality and choice of a restaurant's food.  A well-presented and diverse menu speaks highly of a restaurant whereas a plastic menu with sticky ketchup all over it and few choices would be enough to make me leave.