However, a packed chart built on an atomic CFG does not make available all of the features that are important to many CFG-based SRL systems.
the very useful treepath feature, which lists the categories touched by walking the tree from the predicate to the target word, only makes sense when you have a complete tree, so cannot easily be computed from the chart (  be lexicalized with their headwords, and this information would be useful in role labeling -but even this misses vital subcategorization information that would be available in the complete parse.