There is a huge difference between doing an autoland at a cat 1 equipped airport when pushed into a corner and not bothering with the expense of cat 3 equipment and certification.
The cat 3 stuff gives you appropriate protections for a bunch of failures, lighting on and around the runway, flight testing to the appropriate tolerances and a bunch of other stuff.
You get what you pay for and a proper cat 3 installation will stand you in good stead where it is needed.
I don't think it is needed in Brisbane for the couple of events a year, a ****load of money for very little benefit, money that comes from the airlines and in the usual way of crap flowing downhill pressure on crews to cut costs, hassles at eba time Yada Yada Yada. Raising fares doesn't seem to be in the scope of executive management thinking for some reason.
But back to your question mikewil, I wouldn't do a proper cat 3 approach at a cat 1 installation unless I was pushed into a corner that I couldn't get myself out of any other way. That is a generalisation but you get my point, though I would happily do a cat 3b approach at a proper cat 3 airport any day of the week.