I believe they meant to argue that it is high-risk because it is inefficient in the sense that you expend a lot of energy which may or may not pay off. But sinc

I believe they meant to argue that it is high-risk because it is inefficient in the sense that you expend a lot of energy which may or may not pay off. But since it is both high-risk and high-reward, I was also wondering why they used the word inefficient there.