Getting an extension for your ski pylon is optional.
The main benefits of having a higher pylon would be:
1) Slightly easier to get up on a wakeboard. (more of an upward pull lifting the wakeboarder out of the water)
2) Longer "hang time" in the air.
3) Boat will stay on plane better.
Wakeboarding is a very fun sport and it is not difficult.
Have fun!