Why does pokerstars have Cash Rebates And instant Bonuses (StarCoins)

[betzest]

If you play at pokerstars I am curious as to why they chose to have 2 types of Cash bonuses you can purchase from the Rewards Store.

You can purchase Cash Rebates or Casino Instant bonuses...... What is more odd is the casino instant bonuses are less value and come with wagering YET they are far more expensive than just buying cash rebates.

So why is cash rebates cheaper than casino instant bonuses? I really would like to know.......