Hot dogs are good for your dogs in some senses. For starters, sausages are nothing but a form of processed meat. And meat is good for dogs. It’s good for humans too!
When we eat protein from meat, our bodies break that protein down into constituent amino acids. These are the carbon building blocks of meat and when we get them in our diet, our bodies recycle them in order to build muscle tissue, ligaments and tendons, and even things like digestive enzymes and neurotransmitters! In short, we recycle the meat we eat and use it to build ourselves. And the same is true for dogs!
And while it is possible to survive on a vegetarian diet, that protein is not as bioavailable as protein from meat and it has to go through more steps to be made suitable for use. This isn’t a huge problem for humans as we are omnivorous and can therefore perform the necessary steps, as long as we fortify our diets with other healthy nutrients.
For dogs though, this is a problem. Dogs are carnivorous and their natural diet is far more based on meat than the human diet. Therefore, they need any form of meat and this means sausages are better for them in one sense than they are for humans!
There are, of course, some caveats to this. The problem with hot dogs for dogs is that they are a very processed form of meat. Processed meat is simply meat that has been through more steps in its preparation. Something like steak or a lamb chop is just a slice of meat that has been taken off the carcass and then oven baked or fried. A sausage on the other hand is made up from ground bits of meat, often combined with breadcrumbs (carbs), lots of fat, and other ingredients such as salt and sugar for flavor. In short, this is a few steps removed from fresh meat.
This is more of a serious issue for a dog than for a human, seeing as the amount of sugar and salt in a single hot dog is proportionately much greater for a dog’s smaller system. This can lead to more serious issues like inflammation.
This means that if you are going to give your dog a hot dog, you should probably cut it a little smaller so that it is a more equivalent size for them as it would be for you. Hot dogs should also definitely be an occasional treat and not a staple of their diet.