A game of skill is one where your ability to make sound decisions primarily determines your success. A money game is one where your ability to spend money is the primary determinant of your success. Consumers far prefer skill games to money games, for obvious reasons. A key skill in deploying a coercive monetization model is to disguise your money game as a skill game.
King.com’s Candy Crush Saga is designed masterfully in this regard. Early game play maps can be completed by almost anyone without spending money, and they slowly increase in difficulty. This presents a challenge to the skills of the player, making them feel good when they advance due to their abilities. Once the consumer has been marked as a spender (more on this later) the game difficulty ramps up massively, shifting the game from a skill game to a money game as progression becomes more dependent on the use of premium boosts than on player skills.
If the shift from skill game to money game is done in a subtle enough manner, the brain of the consumer has a hard time realizing that the rules of the game have changed. If done artfully, the consumer will increasingly spend under the assumption that they are still playing a skill game and “just need a bit of help”. This ends up also being a form of discriminatory pricing as the costs just keep going up until the consumer realizes they are playing a money game.