One benefit is that your dog is registered in your name and this can help if someone steals your dog. It proves ownership and can help in the even that your dog is stolen.
Another good point of AKC, CKC and other registrations is that it helps prove that the dog is a purebred by keeping track of the dog's ancestry and heritage. This helps new owners and other officials see what kind of lineage your dog has. Does the dog have any champions? Having a purebred dog that performs in events is a sport that many enjoy.
The AKC holds breeders to high standards and any dog registered has to be scrutinized to make sure they are really the breed and characteristic known to be that breed. AKC breeders take special care of their dogs, abide by strict standards, make sure 100% of their dogs are registered and often participate in Breeder of Merit events.
Registration also ensures that when you buy a dog the owners can provide a history to show the dogs are purebred and of the quality that you want when getting a purebred dog. Often when a dog is purebred there are certain traits they will have that are desired and sought after such as black liner around the eyes, black nose, shiny silky white hair and more in the case of other breeds.
Make sure and get your dog registered as soon as you get it home or ask your breeder to help you do it online before you leave with your new puppy!