Why do Iguanodon's have a rearly long claw on each foot?

Iguanodon doesn't have a long claw on each foot. They do have a long claw on each thumb, which they may have used for defense. Dinosaurs that do have a long claw on each foot are dromaeosaurs, such as Velociraptor and Troodon, and they used these long, curved claws for hunting by stabbing and slashing their prey in soft areas with blood vessels.