Personally, I think there is a lot of magic yet to be discovered in dynamically manipulating the CSSOM (CSS Object Model).
Case study: If trying to manipulate some ~100 inline-block elements into a grid, with dynamic (say, zoomable + pannable + screen size dependant) width, height and offset. It makes way more sense to programmatically modify the stylesheet using the CSSOM API with fast calculated values, rather than applying unique styles to each of those 100 elements in the DOM, O(1) vs O(n) - yes?