I just stumbled an earlier thread about a @type attribute for <p> , and there was a question about use cases. Here is one I can think of right away. In the days long ago, when I regularly thumbed the Classics review journal Gnomon, I always appreciated reviews that had a main argument in larger type and subsidiary stuff in smaller type.  So you could read the whole thing or skip the fine print. You could  model the fine print stuff as inline notes, but I think of notes as bits of text that sit explicitly outside the text stream, while the alternation of paragraphs in Gnomon stays within a sequential reading order.