Some dogs are very food motivate (overly so). But others are more incline to do things for a toy or "petting" reward.

My dog is not very treat motivated (we save them for special occasions). He loves his tennis ball- he'll do anything for me to toss it.

I personally feel that if your dog reacts well to treats- why not give him treats? If you think the dog will become over weight from eating too many treats- then cut back on the food you feed for meals. Its all about balance.

Considering the age of the puppy- I think treats were the best to motivate him. He did a great job for his age!