compressor stall,
an ICAO PPL with a NVFR holder can sit the 14 JAA ATPL subjects and walk out with a CPL and a frozen ATPL as long as they meet the hourly requirement and pass the JAA CPL flight test (which can also be done in WA), if you meet the hourly requirement for ATPL you will walk out with a full JAA ATPL.
The JAA CPL fits on top of the JAA ATPL in a nice way whereas the CASA CPL and ATPL do not apparently but i could be corrected on this one.
Therefore it is way easier in my view for someone aspiring to be a commercial pilot in both EU and Australia to sit the JAA subjects first and then convert that to a CASA CPL which is relatively easy as CASA recognizes overseas CPLs and ATPLs.
The JAA system makes it hard for current ICAO CPL and ATPL holders to convert their licenses, you are required to sit the 14 subjects for them to hand you a CPL or ATPL.
However I believe Qantas (and maybe others?) do not accept (for union reasons???) pilots who hold a converted CASA ATPL but I have no aspirations to work for Qantas so this does not bother me.
I just don't see the point of sitting the CASA CPL and ATPL subjects and then also having to sit another 14 JAA subjects just so I could have both pieces of paper.
Hope i answered your question.