Casinos might choose to give you a free spin or bonus based on your commitment and how frequently you gamble in their casino. However, your tier also depends on how often, you will get bonuses from the casino.
Some casinos, when you are in the VIP tier, at the end of the week, they give you back some percentage from your losses, so that you can gamble and wouldn't feel your losses that much.
Giving out free games based on regularity is a system designed to make gamblers addicted. I remember how my friends that are gamblers used to fund huge amounts of money because they wanted to attract some bonuses at the end they end up losing both their stake and bonus. Casinos giving out percentage of your losses isn't very catchy to me because they would not give you anything significant