As a medical student, I can see the benefits of this, if someone turns up in emergency alone, unconscious, you can look up their medical history with may assist with a quicker diagnosis of the problem, and therefore quicker treatment, and potentially save their life.
As a pilot, I can see the downsides of this, pretty much every pilot has at least 2 doctors they see, one for their medical, whom they see to have their medical renewed only, whom only knows about the perfect health of the pilot, and another they see every other time, when they have the flu, they they break their hand or leg, or any other ailment. Because if the DAME found out about your day to day issues, CASA would likely rip up your medical in a second pending 'investigation'.
I know someone who was going for their medical to enter the airforce, and had an abnormal heart beat in the airforce medical. They did not get into the airforce, but they were also grounded for several months by CASA, and had to spend big money proving that it was not a problem to CASA.
Remember, according to the regs, if you have an illness that stops you for flying for 7 days or more for a Class 1 (30 days for a class 2) [CASA 2015], then you are supposed to go to your DAME before you fly again to get the OK to fly. So that flu you had last week that kept took you down for a week, you had better had seen a DAME before you took the stick in your hands again, or you just contravened a CASA regulation. Hold a Class 2 and broke your hand or leg, then better see your DAME before you fly again.
CASA 2015, 'Reporting Medical Conditions to CASA',
CASA, viewed 10 May 2015,
Civil Aviation Safety Authority - Reporting medical conditions to CASA