The reasons to move from GA to RAA would be wide and varied. Dunno about the loophole thing..
In my case I joined RAA years ago to get a TW endo but that was to give me skills which would have cost me a lot more had I done it GA. Same skills, just cheaper..
I still have a current PPL and medical, but now I have to pay the doctors and CASA every 2 years (used to be 5 until 40YO) and really, I fly 99.9% either solo or 1 pax...
But with PPL I don't pay annually for my licence, where RAA I do. The way I deal with it is - I think of RAA being a magazine subscription and 3rd party insurance with a free licence... so no problem.
So RAA introduced HF so that you have a checklist for personal well-being.. hang on!..not good enough.. now they are starting down the path of doctors and extra costs, apparently, on top of RAA fees.
Side note - I did HF as part of my PPL but this is not recognised and had to do the RAA exam anyway.
I would be interested how many accidents have occurred due to health compared to all other scenarios (CFIT, mechanical, etc). I can't recall many that I have read about, and some are speculation..
Also you could be very healthy and attempt to fly an non-airworthy aircraft and crash...doesn't rule out common sense, does it.
For me RAA has made flying fun again... plowing a Cessna through the sky had become a bit ho-hum where my current ride (Texan) is zippy, responsive and about $50 an hour cheaper.
I may keep my PPL for CTA but probably not worth the $$ for the medical and CASA. We will see in two years.. RPL may be on the cards but why would I want to fly something that burns 35lts/hr compared to 17 at the same IAS? (But I don't own a Decathlon!)