You don't.

There are a lot of things you can do with your reward points. Only redeeming for Reward Points Bonus and Lottery Ticket Bonus are restricted. Other than buying lottery tickets you can also play Hi-Lo game or if you don't want to gamble just deposit the required amount and the restriction will be gone.
This was done because those benefits were heavily exploited by botnets and we want to keep them available to our paying customers.