I don't really have a formed opinion on this subject. (Though I have some experience with certain things where holding back in childhood has lead to potentially much bigger addictions)
But I can tell you that my uncle bought smartwatches to his children. The watches are only allowed to call family members & have GPS tracking on them, have no games, no Youtube no distractions. They are exactly what you are describing, a safety feature. (though the kids regularly dualwear them to cover for each other, so .... :D )