Why your Labrador puppy needs a harness

Mira wears a back-fastening harness when we are walking on-lead near roads. When she was young she once got spooked by a flapping plastic bag, reversed out of her collar and went on a mad BTR on the main road through our village with me flagging down traffic until I caught her Not having a repeat of that thank you very much!
I have never thought of it as anything to do with trying to stop her pulling. I used training for that. Yes, she will still sometimes lunge to see a person or dog she wants to get close to, or a dropped sandwich etc which means I have not trained her properly yet, but meantime she doesn't choke herself in the process.
We have a K9 harness with panniers for bigs hikes.
We have ID tags on collar and harnesses so she doesn't need to wear both