I like the special challenges and the incentive they give to play. However, I absolutely refuse to pay gems for these challenges, which give merely a chance at increased gold rewards. Gems are a resource that I carefully save up for the 3K Ruby chests, or possibly legendary items in the shop.
I submit that paying gems to play these challenges is a complete waste of resources. Does anyone care to dispute this claim? Does anyone find themselves paying gems to play these challenges?