Neither is necessarily "better", but rather they are different design choices. HTML at first wasn't intended to have very much styling at all, and originally t

Neither is necessarily "better", but rather they are different design choices. HTML at first wasn't intended to have very much styling at all, and originally there was some more styling mixed into the HTML itself (like <font>, bgcolor, etc.). Since now we pretty much want to make our webpages look like anything, it seemed to make sense to those drafting the standards to separate the two concerns, since HTML is mostly about page flow structure and data display, and page sources would be even harder to read than they already are if everyone was just putting their styles within HTML tags. If you're looking for a data attribute, it can be hard on the eyes to be constantly sifting through attributes for styling. You certainly can do things to overload attributes and do what you're suggesting (in a sort of hackish way), and you wouldn't necessarily be wrong in doing so if that's your preference. Many people just don't like that. One of the great things about separating styles out of HTML is that they can be contained in files and included separately. With poor connectivity, ideally, it's beneficial to keep the main page source to be as slim as possible so that it can still be downloaded and read even if the styling hasn't yet finished downloading. That's not nearly as relevant anymore, but it would not be surprising if keeping pages lean was a motivator in moving away from putting more stuff in HTML.