Importing files is handy when you have your css in multiple files instead of one bloated stylesheet. See Bootstrap’s Sass files for an example. Every css component gets it’s own .scss file and they all get compiled into one main stylesheet.
The usual imports in a main.scss file are something like this:
1// Reset
2@import "_reset.scss";
3
4// Definings
5@import "_varables.scss";
6@import "_mixins.scss";
7
8// Global Styles
9@imprt "_globals.scss";
10
11// Page specifics
12@import "pages/_about_us.scss";
_
are left alone by sass. They are not compiled. (similar to Jekyll..)