Earlier quoted context omitted.
This. And what about the psychosocial consequences, will it be an improvement compared to the other substances? I doubt it.
While I don't think smartphone addiction should be taken lightly, it's still a far cry from substance abuse.
My personal take is that the net social impact is positive for alcohol, marijuana, hallucinogens, and maybe some of the party drugs. For most people, they tend to be a social lubricant, tool for exploration, and source of fun.
I think that smartphone use probably balances out negatively. I think for most people, they have a pretty severe negative impact on their lives, and for some, an extremely negative impact.
The worst outcomes for drug use are probably worse than those for smartphones, but not by too much in my opinion.