Four of my six GC were given their own tablets for Christmas, including the youngest who only turned three in November. They had been using their parents iPads or phones for games, none are addicted and have many other things they like to do. GD3 has been playing educational games since she was tiny, she also spends a lot of time outside, loves her bike and scooter, likes to paint, dress up, used to play with play dough more than anything else for months.
On the other hand DIL and DS said their boys didn't need tablets, they were concerned eldest GS age 8 wanted to spend too much time playing games on the computer. Plus they have many computers, laptops and an iPad, DS works in IT. GS would not want to go out with them because he might miss out on playing games, even though he was restricted to the time he was allowed to play. They finally decided both boys could have an hour playing games if they earn a token for half an hour practising on the piano or other school work. It's worked really well, GS8 is now relaxed about his time on the computer, his piano playing which was very good has improved and GS6's reading out loud has come a long way since they started with the tokens. Also the boys play other games together and have many other activities.
GS's neighbours, boys recently turned 8 and 6 are not allowed to play computer games at all. When they come to GS's house to play the first thing they want to do is play on the computer. I will be interested to see who in years to come, when there is no parental control, will spend the most time on computers.
One thing I am very much against is allowing children and young teenagers to be on social media sites.