Would you put your child on a leash/a child harness? Why or why not?

This morning I went to the park close to my residence to jog and I noticed a mom who had her baby on a toddler leash. And each time I am going to run an errand I see just a few youngsters primarily toddlers on leash. My very own cousin who’s two weeks older than me was on a leash/baby harness after we had been toddlers whereas I used to be in a stroller. Is placing kids particularly younger kids on toddler leashes turning into extra widespread and are they factor.