Studies show that when you reward kids for behaviors like reading, that it becomes about the rewards, not about the reading, and when the reward goes away, so does the behavior. (See Alfie Kohn's "Punished by Rewards.)
I think many studies end up with results that the researcher wants to find. Of course it makes sense that people, including children, will do something they don't care for as long as they are rewarded for it. Then, if the rewards go away, so does the behavior. I also believe that you are either a reader or you're not. If you're a reader, you either know it or you don't. Just like trying new foods or anything else new, sometimes you need an incentive.
A true reader doesn't need an incentive to do something they love. However, if you can do something you enjoy and get something out of it at the same time, why not?
Your mileage may vary.