Compared to PropBank and Semantic Frame stuctures, they have the advantage to be connected and complete, i.e., capture all argumentative, attributive and coordinative dependencies between the meaningful lexical items of a sentence, while PropBank and Semantic Frame structures are not always connected, may contain either individual lexical items or phrasal chunks as nodes, and discard attributive and coordinative relations (be they within the chunks or sentential).
they constitute incomplete structures that drop not only idiosyncratic, functional but also meaningful elements of a given sentence and often contain dependencies between chunks rather than individual tokens.