Flyer517, I'm glad we can have a healthy debate.
I've flown in/at BK plenty of times on navexes.
I think the downside to Bankstown is that you often spend far too long waiting on the ground. For the benefit of the OP, if the engine is on - you're paying! Long wait times at the holding point are problematic.
I agree that getting comfortable in CTA at a busy class D is not necessarily a bad thing. That said, I find it amusing how many people who have learned to fly at a Class D airfield struggle when they go to a busy CTAF!