Having to autoland on a non approved ILS/Runway in actual Low Vis is a very scary scenario and to be avoided at all costs.
Not true.
Aircraft with an autoland capability can auto-land successfully on any Cat I ILS facility. It's all the bureaucratic garbage required to get these Cat I ILS's up to Cat III status or better. PER,SYD,MEL & BNE should all be Cat III B ILS approved - but who is going to pay for it and sign off the paperwork. You only have to read the crap about the NAS to realise how reluctant to (aviation) change Australians are.