It’s been years since I’ve touched it, but clicking the congressional bill XML link and seeing a perfectly formatted and readable page reminded me of exactly why XSLT has a place. To do the same thing without it, you’d need some other engine to parse the XML, convert it to HTML, and then ensure the proper styles get applied - this could of course be backend or frontend, either way it’s a lot of engineering overhead for a task that, with XSLT, requires just a stylesheet.