I think I found a slight mymaccas points hack.
For 2500 points you can get a McCafe beverage of any size with any milk substitute. I got a Large Iced Latte with soy milk (value $5.75) for completely free using 2500 points.
Compared to the other items you can get for 2500 points (apple pie, fruit bag, small soft drink etc.), I think this is the best value use of 2500 points.
Old news, not a hack though