Here's interesting scenario:
A private pilot who has been flying a Cessna 172 for a couple of years and their flight review is about to expire. A grade 1 instructor cannot complete this pilots flight review if there is any "training" involved unless he does so operating under a Part 141 Certificate. CASA recommend all flight reviews include a training component.
Now his mate who learnt to fly at the same time and has been flying the Cessna 172 buys a Harvard. A PPL holding a flight instructor rating with design feature and flight activity training endorsements can train / issue constant speed prop, tailwheel, retractable undercarriage and aerobatic endorsements in the Harvard. The design feature endorsements would satisfy the requirements of a flight review and no 141 certificate or CPL required.
Seems like the people developing the new rules can't let go of the old rules, yet create these sorts of glaring anomalies. BTW, the RIS used the flexibility provided by Part 61 allowing instructors to do flight reviews independently as a selling point.