To nobody's surprise, I spent quite a bit of time playing the Challenge Machine at the end of the game
Illustrated by Framestore
Kaya, Orzhov Usurper has seen small amounts of play, but her minus ability is much more restrictive than Dakkons
The reason rarity matters has nothing to do with deck building in Disney Lorcana or even gameplay, but rather it determines what cards players will get from a booster pack
for example, your cool counterspell should be blue, your hasty creature is likely red, a card that cares about power is green, and so on
Now, I dont have a lot of PSA cards but I have a lot that do plan on (eventually) getting graded and think I have a pretty good grasp of what cards have the potential to get