However the article makes the mistake of saying that RSS is about "obtaining content from a website without having to visit the site itself". That's definitely not true.
RSS is about being notified of new articles. Subscribing to an RSS feed is like subscribing to a mailing list.
But it won't deliver the content reliably — many RSS readers restrict the HTML being rendered, for good reasons I'm sure, but they mess it up, there's no standard for what kind of HTML is accepted of course, so it only works well for textual articles, but rich text (e.g. images, CSS) is very problematic.
On my own website (alexn.org) I had many problems with rendering articles, due to images and code syntax highlighting, enough so that I decided to no longer render the entire article in the RSS feed, I prefer to deliver just a summary.
Being notified of new content, with a good summary, is all you need. If a website's readability is shitty, you can always invoke the browser's Reader View (Firefox, Safari) or open it with Pocket or whatever.