All games have purchases, even King's Raid. What I was talking about were the things like a divided in-app currency and "premium" summon. King's Raid has focused purchases more on cosmetic items that still give a bonus, but reduce the obvious gap between paid and unpaid players in terms of ability to progress through core content. A portion of the premium content can still be obtained through progression, even some of the cosmetic items. By having three separate tiers of summon, the registration rewards are not even a standard summon. Instead, you provide a full low-grade draw, just enough standard currency to appear generous, but keep the best content locked behind a purchase. It becomes almost impossible for unpaid players to start on the same level, even with extremely good luck. This places a lot more pressure on players to become investors. Rather than evolving from free players into paid players, it often has the adverse effect of pressuring them into leaving the game.