The VIP casino club also known as 'lounge' is the rewards program that gives more cash and bonuses to loyal players. In general every player earn points by playing for real. Using a VIP club you can use these points to achieve highest level through the rewards scheme.
Most VIP casinos have personal managers, invitations for special events, exclusive deals, private rooms and more. It's absolutely the same with mobile casino apps or sites because there is no difference when we play for real.