Variables in Dialogue Wise are the same as variables in any other programming language. They are used to store information. Contents and Expressions can contain any number of variables and they help you to generate dynamic content based on certain scenarios.
Using the same example that we saw in Expression., consider the content in your Dialogue to be:
I love @food
If your Variable @food has the value, say, pizza!, then your content would render to:
I love pizza!