randomness is a powerful tool for casinos to stay profitable while keeping the game reasonably fair (meaning a fairly consistent chance of losing) for the players
Well, in fact randomness cuts both ways
And it is randomness that gives gamblers hopes to win. Casinos stay profitable not because of randomness but rather in spite of it. When you bet long enough, randomness gets removed from the equation entirely. And what remains, as you might have already guessed, is called house edge. Randomness can override the house edge but not for long, so technically it is against the casino. The latter just uses it to lure gamblers into believing that they can win, and they can in fact if they are lucky to conquer the odds and wise to keep their wins