In the beginning when people first started gambling it wasn’t on slot machines but card games instead but as time progresses so does adding new things into the world and we now have slot machines. They started out as a 1 arm reel slot that you had to pull the lever every spin.
Arms get tired and people really didn’t care for buckets of nickles they had to carry around which were heavy. Now we have buttons to push and tickets for winnings, much simpler way to play slots. You still had to go somewhere there was a casino and many places their is not one close so then came the online casinos as they seen a market for having the casino come into your home. It has been a common factor in people’s lives for awhile now and users enjoy the convenience of it. Of course when they started out they were pretty much as boring as those 1 arm slot machines but now they are not much different than regular casino as they invented new ways to display the slots and added new features to them. Again in recently couple years they had to go back to the drawing board so they could also provide mobile slot machines and this will advance in the future as well.