By that, I mean, If you choose a 65 ATAR course (and I know that doesn't mean it's easy) so let's say you pick a course that everybody knows is a bludge, suuuuper easy.
I chose an IT degree to begin with which required a 55 ATAR to get into. I managed an 80 WAM overall and was admitted into a masters at monash (a while ago now, lol). My uni didn't even use GPA, but i'm sure if I applied somewhere that did use it, they would convert my grades using their own process.
To add onto strawberries' comments, you really do need to pay attention especially to the GPA. I don't think many unis use GPA anymore (WAM/avg preferred), and if they do, they use different scales (e.g. 4-point vs. 7-point etc).
What you need to consider is that most degrees require specific content to be taught in order to be accredited (there are so many, depends on the discipline). So the idea is that at least at the Bachelor level, content will be
similar. Of course there are differences in teaching/research etc depending on the uni you do decide.
To get a HD or even a D at uni level is a great accomplishment in itself. They are difficult to obtain (nothing like high school).
tl;dr not much difference in a general sense.