What's actually being discussed is the reverse, or "clear: both" for
good measure. For a right-floating image, a break styled "clear:
left" prevents strict adherence to the box model from forcing text
into a teeny-tiny margin if even a single line of text aligns
horizontally with a floating element (image). You may sometimes wind
up with an slight gap between paragraphs, but it's a far sight better
than the alternative.
Nobody suggested that the images themselves should clear left.
-- Austin