Unless I've misunderstood your post, you already have enough SC for Gold (700 required - 600 to retain). You say you have 800 SC.

The benefits of Gold (in Australia) are express security, extra baggage allowance, free access to Qantas Club, priority baggage handling (although as often as not priority and business come out of the carousel last!!!), a little bit up the pecking order when it comes to seat choice.

Overseas (and in Australia) if you need to check-in, you can do so at the Business Class desk, you have access to the OW lounges and, I think, Emirates, if you are flying on relevant metal, e.g.
AY, MH etc..