My youngest, Carson, is 18 so none of my kids grew up in the era when little kids played on tablets or phones, so I don't have any experience with this. I do know that Carson is on his phone WAY too much.
If tablets had been around when he was 4, I like to think I would have never let him play on them, but who knows? Maybe I would have. I can say that I get annoyed when I see little kids at a restaurant with their family, wearing headphones and playing on a tablet all through the meal. (Whenever I say that, people blast me and say, "Don't judge! That kid might have special needs!" I get that, but let's assume they don't. Besides, me judging them to myself isn't hurting them.