Wait is different than Stay. It tells your dog to pause for a bit, take a breath, before the next action. Wait until... It is excellent for safety and impulse control.
"Wait" for safety
Teaching your dog to Wait at doorways can prevent a tragedy. Have them Wait before getting out of the car to give you time to get a good grip on their leash. Tell them to Wait before going outside so they don't take your knees out bursting out the door. Have them Wait before going out the door for a walk to make sure they are connected with you.
Wait is also great for teaching your dog impulse control and basic good manners. Sit and Wait while you clip the leash on so you aren't wrestling with a twirling dog, struggling to get the leash on. Wait while you put their food down and move out of the way so you don't get popped in the chin by an excited jumping dog. Teaching a dog to slow down and Wait also keeps them from knocking down small children or elderly people in their excitement.
Wait is an exercise for us, too!
There is a saying that dog training teaches you patience. Having a dog who does what you want them to do and behaves the way you want them to behave requires patience on our part. Dogs learn faster and cooperate more with a patient owner.
Standing in your driveway for 45 minutes waiting for your dog to stop trying to push their way out of the car takes patience! Waiting for your dog to sit still before you clip their leash on takes patience. Waiting for them to follow the Down or Sit cue when they don't get it right away takes patience. The good news is that it only takes a couple of times of waiting them out for your dog to get the picture, and they will start to do what you ask right away. It's when we are impatient because it's not happening fast enough, throw up our hands and give up that they learn it's ok to ignore you. They get what they want anyway.
The other good news is that aversive punishment is not necessary to have a cooperative dog. Aversives (jerking the leash, delivering a shock, smacking their nose, etc.) have a high risk of fallout and reduce your dog's trust in you. Instead, we withhold the thing they want (leash attached, door opened, getting out of the car, etc.) until they do what we asked. It's the Grandma Rule - you can have dessert only if you eat your vegetables first.