This is not just the gacha component. Take Candy Crush, Simon's Cat, Pokémon Go, etc. You know what the prizes are, but the gameplay is still subject to various

This is not just the gacha component. Take Candy Crush, Simon's Cat, Pokémon Go, etc. You know what the prizes are, but the gameplay is still subject to various degrees of randomness, and it's statistically calculated and adjusted to cause just the right tresshold of repetition and frustration to maximize microtransaction revenue.