The deck system is free and gives raiders coins as well, which is the currency for their cosmetic store. The cosmetics and raider coins is where they are making ongoing revenue to support the live service part of the game. The "gatekeeping" is necessary to keep players from going through and unlocking the free raider coins, and it also keeps players engaged playing to unlock the pages they want. Essentially, these free decks give players incentive to remain engaged and rewards their time playing. Its a free battle pass.
