I have ambivalent feelings here. Dogs do love playing tug, and it is used a lot to motivate and reward highly-trained dogs such as sniffer dogs.
But if we want a dog to hand over whatever it has in its mouth to the lightest touch of its owner, then it is debatable whether teaching it to tug is ever wise, especially with those breeds that can be fairly opinionated.
Therefore, I would not use it for any dog that has to retrieve game.
For other dogs, tug can be useful as a reward, but we have to instil manners.
Teeth should never be allowed to touch the hand, no matter how lightly, and if they do, the game stops, the handler drops the tug item and walks away.
It is fine for the dog to “win” and keep the toy sometimes, but it should also learn to give it up on command.
Owners should be careful not to tug too hard because of the risk of damage to teeth, especially in a developing mouth.