I'd agree too. "Smartphones" have a lot of functions in them. A lot more than fun and games. Children under 10 should not be playing around with smartphones. In my opinion they should be exposed to books, outside games and probably reading in general.
But if parents can limit or teach their kids on how to use a "smartphone" for reading, it should be alright.... right? NO. lols.
If you're using a "smartphone" just for reading, then just get a book. lols. Kinda under-using the smartphone if you ask me.
Anyway, I don't think "smartphones" are bad its just that if you're trying to teach kids English, numeracy or colours or something then there are more kid-specific, brighter coloured tools/toys that can do that. Part of the fun is that they can play around with them, kid-friendly and you don't have to worry about it breaking and costing hundreds of dollars.
I would agree for teenagers to have phones for emergencies or calls. I just don't think a "smartphone" is necessary. Or at least have a smartphone (if you can afford it like bread) but don't use those social apps or games. I think is a bad habit to start young. Smartphones are great, but need to keep the limit on its usage on young children.
But that's just my opinion. End of rant. lols