What can full-grown dogs do that puppies can't do?

Answer 1

Are you asking what the benefit is of getting a full grown dog rather than a puppy? If you choose wisely you will get one that is already trained by previous owners, saving you the trouble of having to train it. That is the main advantage.

Answer 2

It depends on the age of the puppy, and the breed of dog.

Newborn pups can barely do anything by lay down, wiggle, eat, and cry. They can't even defecate on their own!

A four month old puppy can not bay/howl quite the same way an adult blood hound or husky can. Also, while they can jump, it shouldn't be encouraged as it puts too much strain on their still-developing legs. They also should not be going outside unless they've had all their shots.

At six months, the dog can function as an adult, and some can even breed at this age (though that has a lot of health risks!). The only things they can't do that their older versions can would be things that require their full height, like maybe counter Surfing... not that counter surfing should be encouraged in the first place.