Irrelevant style guidance in <i> element definition?

[LJWatson]

"Authors can use the class attribute on the i element to identify why the element is being used, so that if the style of a particular use (e.g., dream sequences as opposed to taxonomic terms) is to be changed at a later date, the author doesn’t have to go through the entire document (or series of related documents) annotating each use."

This might be a practical suggestion, but it is irrelevant in semantic terms, so should it really be part of this definition?