I love HTML more than you could know. When combined with CSS, you can make really rich documents.

HTML lets me put semantic information that can be selectively presented to the reader, respecting their preferences in how much of the extra information they want to show.

Using CSS, I can display abbreviations in select appearances, then hide them later - but it is still available for the user to request (by mouse hovering on typical desktop browsers) if they forgot what it means later.

Of course, you could do the same with other tags, but the beauty of a standard semantic tag is that other third-party users might be able to make sense of it too.