Earlier in the same section, there was this:
Visual user agents must ensure that the content of the Q element is
rendered with delimiting quotation marks. Authors should not put
quotation marks at the beginning and end of the content of a Q element.
User agents should render quotation marks in a language-sensitive
manner (see the lang attribute). Many languages adopt different
quotation styles for outer and inner (nested) quotations, which should
be respected by user-agents.
My suggestion is consistent with W3 recommendations.
Don't be obtuse, Jason. Grammar is about how language is used. Typography is about how it is rendered. There are bits of overlap simply because many typographical conventions have been adopted by grammarians. Even your beloved paragraph is a typographical construct. Typesetters, and that includes the olden monk scriveners, began marking changes of voice, topic, tenor, &c. to make reading easier. The pilcrow (¶) was the symbol used to mark the change. Then came a line break before the symbol, then the symbol was removed leaving the familiar line indent. And so, we have paragraphs as typographic artifacts.
Grammar and typography are not mutually exclusive. They each have a part in the finished product. Typography is the area of decision making when you decide, for example, how to render a heading; font size, font family, weight, flush left, flush right, centered, etc. How will you display a menu? Oh, and the blockquote? Indented, italicized, use quote marks, other, all of the above? Parenthetically, I read a lot of research papers, and block quotes are ubiquitous. I think I've seen every possible method of setting the quoted text apart; indented, quote marks, italics, bold, smaller fonts, different font families, and any and every combination. None had jack to do with grammar, and everything to do with typography. The important issue is whether the quoted text is identifiable as separate from the authors' text. All of the methods do the required job, though some are less than æsthetically pleasing.
Or, do you not use style sheets?