If you tap the Battle tab , then tap the Guide icon , and scroll down to the For Advanced Players section, you will see that there are additional missions that reward Item and Supporter cards
This type of value system exists in the Pokmon TCG as well, so lets see what that looks like: This is straight from the Pokmon TCG rulebook, and its telling
New expansions and updates are available instantly for those who choose to spend money
If you want something a bit smaller in scale, cards like Sparkmage Apprentice, Ghitu Shaman, and Basalt Ravager can really bring the beats
Mason who gives you your first starter deck of your choosing and takes you through a step by step tutorial on how to play the card game
Suffice to say, there are plenty of foil uncommons that have gained value over the years