HTML does have it's limitations, but I think it still serves well for certain UI uses. The original post was asking about making simple scrolling text. That's just one line of CSS, as I showed.
As another example, suppose you want to show a scrolling data table in your game. Do you really need a whole stack of built-in plugins to handle that, which would probably still be only a fraction as powerful as HTML, when you can just use a HTML table? There's also plenty of free guides out there for learning HTML and CSS, it's incredibly powerful, and you'll be learning industry-standard technologies that you can get a job in rather than some tool-specific details.