You guys are both making it way more complex sounding than it really is. The cards count as ranks on those. The banner that appears is just telling you how many kills you have to the next rank. The old ranks in vanilla unlocked better rewards after rank 2. The ranks count for 5 cards each. Other cards unlock for 10 or 15 points. Once you reach the highest rank of rank 3 it does not add any points to your score. That's how it works..... If you look at the cards you can actually see the points it rewards in the corner..... Not sure how you guys both missed that.....