Just that.
I see it daily, multiple times of the day. I live on a quiet residential street that has two nurseries and a primary school and many of the people I witness on their phones are driving with little children in the car.
I have never ever done it myself because there is no need. So who are the people who do? Where are you parents in my postcode who drive and look at your phones? Some of you will be regular posters on MN. Why do you do it?
I'm not expecting anyone to fess up tbh.