Dogs are den animals and many like a place they can curl up in and feel secure.
You can leave Puppy or Doggy home alone with peace of mind. He is comfortable and not forming bad or destructive habits. He also is not going to be confused by your reactions to bad behavior when you return. Remember, dogs do not have the reasoning humans do. When we return and see the garbage rooted through and then punish Puppy, chances are he will not realize what you are punishing him for.