Games like Fifa generate lots of money from selling "packs" in their ultimate team mode. When you buy a player pack, they have a guarantee of containing a fixed number of gold, silver, or bronze players but since the gold, silver, and bronze players can have vastly different ratings, it doesn't disturb the balance of the game.

People spend hundreds of dollars buying packs in that game and end up winning not a single useful player while someone can win the best player of the whole game through a free pack they received from an in-game tournament