I believe they put it in there to actually make the critical things less confusing Squawk7700. At Archerfield people wouldn't always realise when they did and/or did not need clearance to cross the Dirt Strips (AKA, not realising they're active and needed a clearance), so to make things easier they just make it that you ALWAYS need a clearance, yes the calls and readbacks are a little more confusing and long winded BUT at least it helps stop people from crossing Runways they shouldn't. Method in the madness?