The thing is, we cannot think of CSS being just for the browser anymore. More and more stuff are being typesetted or presented/designed using CSS: mobile and desktop applications UI, graphic design (the SVG vector format standard uses CSS), as well as all sorts of printed materials. Whether this is a good idea or not is another question, but it's a fact. So CSS kind of has to offer fine-tuned control over many things including tiny details.
See for example Paged.js [1], a way to use HTML and CSS to produce printed books, with complete control over the rendering and an attention to details almost of TeX level's. Using web technologies as source format tremendously facilitates the production of various electronic formats in addition to the printed/PDF version, such as ePub and well, web pages, which need free flow text that print-oriented format do not allow for obvious reasons.
All this to say, I agree with your feeling if we stick to web browsers, but CSS is so much more nowadays.