Every time you spin in ANY slot, you get the fireball points which are used for the World Slots League ranking system. You earn more fireball points with higher bets and x2 points playing in the High roller club.
Once the season ends (which is indicated in the WSL), the more points you have, the higher chance you qualify for a higher division.  Higher Divisions increase their store purchase and scratcher winnings.

WSL Divisions:
  1. Immortal - Scratch and Win x5 - x 100
    2.                    -  Store Purchases + 50%
                        - Legendary Stamp - x3
  2. Legend I - Scratch and Win x4 - x 75
    3.                    -  Store Purchases + 40%
                        - Legendary Stamp - x2
  3. Legend II-  Scratch and Win x4 - x 50
    4.                    -  Store Purchases + 30%
                        - Legendary Stamp - X1
  4. Master I - Scratch and Win x3 - x 40
    5.                    -  Store Purchases + 20%
                        - Legendary Stamp - x6
  5. Master II - Scratch and Win x3 - x 30
    6.                    -  Store Purchases + 10%
                        - Legendary Stamp - x5
  6. Expert I - Scratch and Win x3 - x 20
    7.                    - Legendary Stamp - x4
  7. Expert II - Scratch and Win x3 - x 16
    8.                    - Legendary Stamp - x3
  8. Pro I          - Scratch and Win x2 - x 14
    9.                    - Legendary Stamp - x2
  9. Pro I          - Scratch and Win x2 - x 12
    10.                    - Legendary Stamp - x1
  10. Rookie    - Scratch and Win x1 - x 10