In a casino, either online or land-based ones, players will have to encounter COMPS or shall we put it “complimentary.” These are perks or freebies provided by the casino management or host.

In land-based casinos, high rollers get the most and the best complimentary available, with free limousine rides, discounts to free hotel accommodations, free drinks and what nots.
The reason for these is that the casino’s management takes care of the players and would like to keep them coming back to their place than transfer to somewhere else and somehow reduce competition. The more wager the player makes, the better comps they get.

In an online casino, they do not offer hotel accommodations, free drinks or limousine rides. Because obviously, online gamblers would absolutely have no use for that when they are already in the comforts of their homes or pretty much anywhere.
Comps online are rated and are computed. Since there are thousands and thousands of online casinos, the competition is tougher than land-based casinos. Therefore, these online casinos offer comp programs to attract members and keep them coming back.

Comps are then rewarded depending on the amount the online player wagers in a game. The more they wager, the better points they get. Most casinos offer comp points as complimentary money, once you have accrued a certain amount of comp points, then it is available for real money conversion and can be added to your pay out.
In other casinos online, the more you wager, the better comp rank you get until you reach their VIP rank. With such rank, a player can get rebates with losses and they are entitled to bigger deposit bonuses. Other than that, some casinos offer comp programs where you can use your accumulated comp points to buy merchandise or gadgets.
Remember that the more you wager, the higher the comp points you get.