The Eww browser is fully compatible with terminal if you run Emacs non-window mode (-nw option). It supports both HTML and CSS, and render quite nicely. Much better than any terminal web browser I used.

The browser is for looking up online documentation not available in your local machine. For example, sometime a man page is not available in my local machine. I can invoke a google query right inside Emacs and open it immediately without involving heavy weight browsers.

It is really nice to read online book like Practical Common Lisp: http://www.gigamonkeys.com/book/, and directly copy the code and paste to your REPL without ever leaving Emacs.