Just to clarify how it works, by completing the challenges, you earn FTPA points (distinct from your normal Full Tilt Points) with which you can purchase goodies in the FTPA store (distinct from the normal Full Tilt store). However if you wish you can also convert your FTPA points into normal Full Tilt Points by chunks of 5000 min.
Apparently you can repeat each challenge 10 times, so you can keep doing the easiest ones over and over again.
Thank you Daven for bringing this to my attention.