RANZCOG may allocate a fair number of potential points to academic achievement, but basically nobody would get many of them.
Like, to get those points you need to have topped your medical class overall, topped your medical class for O/G, gotten first class honours overall for your degree, won a Dean's medal... And they specifically exclude pretty impressive things like 'got first class honours in an individual subject'.
So while there might be a large theoretical haul of points for medical school academics for RANZCOG applications, basically nobody is going to get more than one or two of those 10 points. In other words, it's not really going to be much of a differentiating factor between most applicants.
And anyone who manages to get anywhere close to all 10 of those points is a superhuman who would most likely blow other applicants out of the water anyway. The kind of person who tops their med class, also tops their class in O/G, gets first class honours for their medical degree, wins multiple prizes and a Dean's medal etc, is pretty likely to have a kickass CV in other areas as well.
My point is, even in a CV scoring system like RANZCOG's, medical school academics isn't likely to be a hugely differentiating factor between applicants (except for applicants who are incredibly impressive anyway).
By all means, go for prizes, first class honours etc. But don't feel like your career is screwed if you don't top your med class.