It is my opinion that raw is the best diet for a dog. My preference is the predator model instead of BARF. Dogs do not digest fruits, vegetables, and grains.  They have to be made into a pulp in order for the dog to digest them. Green tripe is rich in nutrients for a dog. As someone mentioned it is already in digestible form as it was already broken down by a herbivore. 

In in regards to kibble. Dogs can survive on kibble and on almost anything. Kibble is full of fillers and other things that a dog can’t digest. It cheap. They often contain dyes, and other items that are known to cause carcinogenic. But it is relatively inexpensive. It is convenient to obtain.