Welcome to the forum; especially as you have an intelligent first-post comment to offer, which is not all that common. I have one area of disagreement, one otherwise, and a short, but intense rant in response.
In which case, it is preformatted text, no?
Or if I have to style a specific phrase within a paragraph, like in different font size and color, because you just want to highlight it visually.
Correct. I think of the span element as a segregator, meant to provide a separate hook to semantically non-specific content.
Oh and also, classes for microformats.
What a kluge! The whole Microformat thing is a work-around (well designed, albeit) for IE's lack of support for xhtml. Unlike the tables for layout work-around that awaited css-p support we knew was coming, this work-around has no end in sight.