Yes Biatch, I imagine he does mean it seriously. Its a perfectly valid question.
Why? Because in other parts of the world (read most/all of the others), you would be specifically cleared for the Y or Z approach, because they are different approaches.
MEL, SYD and BNE there happens to be no issue, as the only change between the charts is the use of ILS vs Airport DME (although why Brisbane is the opposite to SYD and MEL is beyond me). But in many cases that is not the only change between a Y and a Z approach. There could be different minima, a different missed approach, any number of things. They are, again, different approaches.
Its a relevant question for someone who doesn't do Australian airports day in, day out.