My children will not have phones until they start high school and were given tablets around the age of 5 and 8 which was a lifeline during covid lockdown due to online learning.
We have set times on our children's devices so once they have reached the time limit, it won't work without parental authorisation.
For my youngest, having access to such a tablet was a lifeline for him, he has selective mutism and is mostly non verbal at school.
During lockdown one of the parents found a child friendly messaging app for the children to be able to engage with each other (you could get the messaging app on a tablet, mine don't have a phone).
As time has gone on, he has managed to speak to his peers behind the screen. It was truly heartwarming to hear him talking to his friends this way, it is obviously a face 2 face issue for him, he continues to communicate this way out of school with his friends.
He is still mostly non verbal at school but does now manage a whisper and I am pretty sure it's all thanks to allowing a device in his life which gave him the courage to show others how wonderful his voice sounds.
We do have a rule of no devices at meal times, including out and about, however, not for me to judge others who do, perhaps they have their own reasons. Although, I can honestly say I have never really seen preschoolers with screens attached to their hands while out, or even primary aged kids to be honest.