Smartphones are good and we shouldn't demonize them.
Judge the tree by its fruits. Children are showing very real signs of addiction, and unlike known quantities like video games, or TV in past generations, parents are being pressured into handing children a device, usually completely or effectively without any safety controls, a private screen with which everyone in the world, every corporation, foreign country, friend or foe, can pour propaganda, toxicity, lies, porn…
You sound exactly like the people who were freaking out about comic books and video games. Moral panic, forever repeating.