In terms of marks, I went to an extension 2 seminar earlier in the year and they were talking about the showcase. The ones that are selected are generally a high E4 range, but they choose a variety of different ones for every medium. (So they say. They seem to have an affinity for postmodern short stories).
Therefore the ones they're showing you aren't necessarily the best in the state, but they are a sample of the variety of things you can do with this topic. This is how the showcase differs to say, Encore, Art Express, Callback etc.