Clash Royale's system is set up so that the more money you spend to progress, the more money you need to spend to progress. That's because the cost to upgrade c

Clash Royale's system is set up so that the more money you spend to progress, the more money you need to spend to progress. That's because the cost to upgrade cards increases as they level up, so [purely as example because I don't know the actual numbers behind this] a dollar can get you to level 3 but it'll cost a thousand to get to level 10. Most loot box games have this as a general concept because pure randomness ensures that the chance of getting a new unique item from a finite set decreases for each new item you get, but Clash Royale compounds this by geometrically increasing the number of each thing you need to get to upgrade it.