What is so special about this? This is the way websites have been doing syntax highlighting before people started using javascript libraries.
At the very least, this kind of article is informative for that crowd.
I have a hunch that there are a lot of web professionals out there these days who genuinely don't know how to build a web application without JavaScript - POST forms, cookies and the like.
The churn rate on junior developers is probably the single biggest factor in software over the past two decades.
Then you'll end up having a project with highlighting logic in css and js. That's less than optimal