Number one would be the fact that they are simple to play. What are the reasons for the popularity of slot machines? So, 70.32% of the money won by casinos in Nevada came from slot machines! The total amount won by the state’s casinos during that one-year period was $7,327,153 and of that amount, a total of $5,152,988 came from slot machines. are generated by slot machines? Well, let’s take a look at the 12-month period from Mathrough Februto see how much of Nevada’s casinos profits came from slots. And how much of a casino’s profits in the U.S. casinos, the most popular game, by far, is the slot machine. When people hear the word, “casino” most will imagine those colorful slot machines, with their flashing lights, spinning wheels, and handles being pulled by players who are aiming to win the jackpot.