High rollers at online casinos often get preferential customer support with a dedicated VIP manager. They may also have faster withdrawal times and higher limits. VIPs get exclusive bonus offers tailored to their preferences. They can also receive birthday gifts or other presents, or they can take part in special VIP promotions.
Rewards vary with casinos and how much you spend as a player, but what they have in common is that you will get special treatment as a VIP.