...because that's the only place the smokers can play and smoke at the same time. That position wouldn't really make any sense. If they didn't want to smoke, they could just go inside the casino and play smoke- and smog-free.
And by the way, the smog is really only an issue in the enclosed valleys, such as the San Fernando and San Gabriel Valleys. In Gardena, which is not in a valley and is completely open to the ocean, it's a non-issue.