I don't believe the ASIC serves any purpose at all. The Airline Identification Card or Photo Licence is just as effective. If an ASIC, those that require one shouldn't have to pay for it.
The sad reality is that while all those things are a deterrent, it is very unlikely a 9/11 style terrorist attack will come from the Airline Industry again, why because it's been done already. We won't see the next one coming the same as we didn't see the last one, it will most likely come from Ambulances or Fire Trucks, the confusion and urgency of all those lights and sirens, we'll just open the gates for them. The target will be major like the AFL Grand Final. That is how terrorism works.