OK, time for me to throw my tuppence worth in. Having flown for two major competing Asian carriers, the current one for 18 years, both operators ALWAYS have an alternate unless Island reserve is approved. No Australian Port is approved by either of these two carriers so hence always an alternate. To assist at times a redispatch plan was used in the early '90s often using Alice or Tindal for the East Coast destinations or sometimes on an odd occasion even NZ. With greater range/payload capabilities these days I haven't seen one of those now for a good 15 years or so.
Prior to my Asian time, operating for an Australian company, even though an Alternate was not always required we never left home without one.
Earlier in this thread someone mentioned whats wrong with an autoland off CAT 1 when A/L approved. Quite simply, if it is below CAT 1 minima the accuracy of the ground equipment cannot guarantee you will always be in the correct spot. Evidence a 74 (non Australian) some years ago doing just such below CAT 1 minima into YSSY. Left some nice groves in the grass during a last minute go-around and gave Melbourne some free SYD turf on it's subsequent arrival down there.