Style is all. I occasionally write about CSS topics.
When I visit a sports website, I want to see scores, standings and how the league/tournament is run. Usually you see ads, news, content pieces and all the good info is hidden somewhere. With custom CSS, that's not a concern anymore.
The smallest CSS library I've ever written: card-print-css resizes images for printing, cutting and sleeving so you can play test and prototype faster.