The only reason I can think of is that it provides a good lead-in to the 6pm news, assuming viewers don’t switch from Seven’s GC news to Nine’s 6pm News 
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Maybe they’ll extend the Gold Coast bulletin to one hour to get a jump on Nine, from 5pm to 6pm? Then that would move The Chase Australia to a 4pm to 5pm slot, and they won’t receive the local 4pm news at all then.