..the short answer is no; if you're exclusively a novel writer it may not be worth the time and expense, particularly if you're a) an experienced writer with existing sources of reliable critique b) already well-connected within the speculative fiction community. The friendships I formed with fellow writers were the best part of the workshop for me; the actual writing/critique less so, although my critiquing skills have certainly become much sharper as a result. (Note that mileage varies, and most others benefitted considerably more than I did; I write slowly at the best of times and write well below my best under pressure - none of which made me a candidate to get the most out of the Clarion experience.)

I do feel strongly that the short story and the novel are different things (a sentiment Jeff Vandermeer also expressed during the workshop) - and that within Australia something like Varuna or Hachette Livre may be the better way to go, especially if you've already got novels written.