Yes but i think we would both agree that in html/markdown it should be "this is book title" because medium allows it. "format this with italics" makes as little sense as "format this with emphasis" they are both wrong. Interestingly "format this with italics" is right solution in print because we encode that meaning in aesthetics and conventions and i guess thats why people think it is also right solution in web. But even in typesetting program that book title will have class .book-title and same italic in footnotes will be .footnote.book-title