When it comes to gambling, winning from time to time is a must have, otherwise players will lose interest and stop playing. Casinos should make sure that clients win periodically, including fairly large sums. Just as a casino would benefit from occasionally returning some of the players' wagers. Because such cases motivate them to continue playing and making new deposits.
If players were positive that gambling was always associated with only losing, they would not enjoy it and would not do it either for fun or for money. No one wants to lose their money for sure. But if players have a glimmer of hope that they will win sooner or later, especially that they will win a large sum that will eventually cover their previous loses, then such players will play and play.
Casino will return the player's wagers but not in a big sum as they just want to see their player return and still playing more gambling games. They know that with launching many promotions can makes their members return and spends more money so they will do that very often.
Having fun in the gambling games can be just spend the free time without thinking about the result. They know playing gambling have the risks that can cause them lose their money so they will always prevent the big lose and just use the money they can afford. Although they lose in gambling, that will not be problem for them because they already know about that.