The "Touch" cue can be used to move your dog around without physically manipulating them. When we move our dogs for them, they are passive and don't need to think. It is better to teach them to follow cues and do it themselves.
Touch is a useful cue for getting your dog to move where you need them to move without physically moving them. It is good for your dog to be used to being physically moved. Most of the time, though, it is better for them to do it themselves. When we get into the habit of physically moving our dog around, either by picking them up or pushing/pulling, the dog does not learn to pay attention and move themselves when you ask them to. We do all the work for them. Being moved by someone else requires no thought, no effort. Your dog can be totally oblivious to you while you move them around. We see this a lot with dogs who are "put" into a Sit position by pressing on their hips. The dog is focused on anything BUT their handler and not following a cue to Sit. The handler is doing all the work.
It is also good for building confidence in insecure dogs. If a dog does something themselves, they feel better about it than if it is forced on them. Some dogs are nervous about the scales at the vet clinic. If they step onto it on their own power, they will be much less nervous about it than if they are picked up and sat on it or pushed/pulled onto it.
Touch can also be used in place of "Come". It's an exercise many dogs really enjoy doing. If they are enthusiastic about Touch but not Come, then it can be used to get your dog back should they get loose. I like to use it to get my dog to me in close quarters instead of Come, and save my Come cue for when they can get a good running start.