[fadeyev]

LESS or Sass are great in specific use cases. They're especially useful when you're using a lot of CSS visuals (where you have to write out about 3-5 lines just for one property because each browser has it's own version, i.e. -moz-, -webkit-, etc). With LESS you can create a mixin that does this thing (e.g. rounded corners) that also takes an argument and just call it in all the places where you need rounded corners. Sometimes you want to re-use the same color over in many different places. If you change your mind, you have to go back and change it everywhere, making sure you don't miss a spot. Nesting makes the code much more organized (you have to try it to see) since you can see which bit of code relates to which area of the page. It's just neater and easier to view. Each of these benefits on its own isn't very big, but when you start saving time here and there they do add up, especially on large stylesheets.

Basically, it's not really about reducing syntax or size of the file (which does get smaller for large stylesheets), it's all about making the stylesheet easier to build and maintain.