Tug is popular in certain areas of dog training - especially for big working breeds with high "drive" for balls, toys and vigorous playing. Because of this, it becomes one of the best ways to teach your dog discipline and to improve their obedience skills.
In certain camps of dog training, tug is feared as it tends to push dogs to an "extreme" and animalistic place (working dog trainers like dogs who have more of that because that is in essence what makes them workable). They are right that tug can be an unhealthy activity if you don't know what you're doing when you go to play it - that is why it is a good challenge for both you and your dog.
I work with a lot of pit bulls, terriers and other "tough" breeds who like to "go hard." Tug is my way of honoring that determined, intense side of them and ultimately developing better control of those tough breed instincts - what do I mean by that?
Firstly, your dog has that side of them so it's important to be able to control that intensity and also it will earn your dog's respect if you're not constantly trying to stop them from being who they are. Cesar Millan once compared trying to stop a dog's natural breed instilled instincts to trying to stop your child from loving whatever they love - like art for example. He went on to say, with a child who loves art you can either tell them that they aren't allowed to ever do that, but they will just do it behind your back and ultimately resent you for trying to stop them from doing what they are genetically programmed to do. Instead, think of nurturing the interest by buying art supplies and setting up certain times to draw or paint. Your dog works the same way - too often we just try to tell them "no!" and "stop doing all the things that we programmed you to do!" That approach creates resentment and the behaviors you were trying to stop will pop up when you are not looking.
Secondly, tug (for a dog that loves tug), is one of the best ways to teach tons of skills. I teach and refine dog's skills with tug all the time - drop it, leave it, sit, down, wait, stay, take it - these are all fundamental skills that can be built or improved upon with tug.
Watch Georgia and Donovan work on their skills and celebrate their inner animal in a game of tug - notice their willingness to engage in the activity, but stop on a dime when requested.