Most are for show
They arent going to prevent any damage. The RR bar and winch set up isnt going to stop a roo, deer, cattle or sheep from doing serious damage to your GC.
Here in the US most GC owners may encounter deer. Chances may be better in Australia that you may encounter wildlife or stock.
We see livestock at least once week at our herding lessons or herding trials. If I encounter stock on the road and it would be a rare occasion I am not going to use my GC to move them. If I have my collie I just put on on the long line and let her move them off the road. And if not I have a stock stick in the back and will move the stock off road myself. During the winter months if we are working set out I bring my GC to back of the field as shelter and too keep warm.
Most bull bars are all bull and just extra weight to mess up the handling and ride.