[css-overflow-3] why so restrictive on styling fragment descendants?

In section 6.1.3 of Overflow Module 3 [1], it allows selection and styling of descendants of nth-fragments. However, it says:

...the only CSS properties applied by rules with such selectors are those that apply to the ‘::first-letter’ pseudo-element

Why this restriction? Why not allow the descendants of the fragment box be styled with the full range of properties? I would think there’s be a near infinite number of use cases to do so. For instance, using different floating or positioning based on whether an element is in an odd fragment box or an even fragment box (imagine arranging the fragment boxes into two columns).

Is this because of how it can complicate ‘max-lines’? If so, then perhaps the more restrictive styling should only apply when the element is inside a ‘max-lines’-limited fragment box.



1) http://dev.w3.org/csswg/css-overflow-3/#style-in-fragments