My reward points are not even close to 20% so in my calculation it might really take 1 or 2 years before I can exchange it for bitcoin, its not a problem though.
You can also use the WOF bonus to get additional spins for every free roll. So if you're lucky enough, this bonus may significantly reduce the time to reach 100k reward points. For example, swogerino
posted a great result. He won ~12k RP in just 2 days.