My parents used a leash with me when I was a child and I turned out just fine. I was a very active kid and could have easily been squashed in traffic. I really appreciate that my parents purchased this little bit of insurance to ensure I survived being a hyper active toddler. Its unrealistic to expect a parent’s eyes to be focused on their kids 100% of the time. And holding a kids hand everywhere they go is the same thing as a leash except each person has one less hand to use for other things.