If someone gambles at a casino property, they are a customer. It is just that simple. If someone takes the time to join a Vegas Casino loyalty program and allows their casino play to be tracked they are interested in that property and their casino loyalty program.
Las Vegas gambling
To me, a recreational gambler is someone that considers gambling an avocation or hobby; an enjoyable way to spend free time. The recreational gambler has a certain amount of money budgeted for entertainment that they chose to risk by taking on lady luck.