This is one from my collection
They come from Silver Strike slot machines, that look like this:
Most modern casinos don’t have these machines (anymore) because they are mechanical machines, not digital, and the souvenir coins cost more than many casino’s are willing to pay for a “give-a-way”.
Personally, I love them, they are a cool souvenir! There is even a “Silver Strikers Club” that has meets at the 4Queens casino every year (the 4 Queens has several machines still in service, and mints event and seasonal coins throughout the year).