There are quite a few areas where someone might want to test a speed. Eg: checking the speed of a website, browser or Internet connection. Checking the speed of how fast you can type or how fast you are at sports/exercise. With regard to the dollar value, I'll have to let someone else provide that.
Today it got 25 visits! SpeedTest has produced a total of 78 clicks in the last 3 months. Unfortunately CPC is extremely low: an average of $0.015! What might be a reason for that?