Code snippets are pre-written portions of code that you can summon with just a few keypresses. By automatically setting up much of the syntax required in common programming language structures, snippets speed up the mundane parts of coding.
Depending on the size of its content, a particular code snippet will save you anything from the small handful of keypresses it takes to set up the curly brackets of an if statement to the several lines of code it takes to write the skeleton of an entire class or method.
Plus, they are just plain fun to use. Look at all the code that I get “for free” here: