Correlation/Causation issues as others have pointed out.

But also, complete inability of schools to adapt.

Refusing to adapt to the reality that is, students will be living their entire lives with these devices, and that they should be working out ways to ensure student productivity despite their existence, is not the same thing as success.

Teachers are inherently lazy. Its one of their more human qualities. But really they need to adapt, or fail and be replaced.

There was a kid in my class in highschool. We had a school that permitted laptops, one of the first near us, but situationally. Teachers could exclude, or instruct the student to not use the laptop for periods during class. However policy was that students were allowed to use the laptop any time they could use a workbook. This kid was the only one who both had access to a laptop and was willing to risk damaging it by bringing it to school.

Math class with this kid was:

1. He plays games on his laptop unless the teacher was looking, in which case he would be solving problems in excel or notepad. Proficient alt tab user.

2. At the end of class, he would copy out all the answers from the back of the textbook to his workbook, and he would hand that in.

English was different. In english the teacher built a relationship with him and engaged him directly. If he was unresponsive he might be forced back to attention somehow, asked a direct question about the text, but that was true of a lot of the students. The entire class was a discussion on book content. When he used the laptop, he was using it to write notes because he was engaged through positive reinforcement. If the teacher caught him playing, the teacher would on those rare occasions, engage him about the game. Often, he had finished his assigned reading\tasks early and simply drifted over. In that case he was left to play because he wasn't disrupting anyone.

Phone bans are a crutch for lazy, uninterested educators. Kids need to be prepared to live in a world with these things in their pockets. The correct dopamine reward feedback loops are not going to be built by banning them entirely. And being better at rote learning and regurgitating ancient course material isn't a strong indicator, if it was even an indicator, of better student outcomes.

Perhaps I'm just lacking in imagination, but I'm not sure how having smartphones in class meaningfully enhances the educational experience. I could see a tablet for note-taking being useful, perhaps. (Or a more limited device like a Remarkable, which IIRC isn't a general-purpose touchscreen computer.)

Kids can prepare to live in a world with these things in their pockets outside of school. Sure, primary school is about learning all sorts of things, not just what the teacher is lecturing about. But it doesn't have to be about everything, and I think it's fair to make the call that the distraction caused by smartphones (especially with all the apps designed to addict users) outweighs any positive teachable moments with them present.

Your anecdote is interesting because it didn't really bring me to the same conclusion. Kids aren't going to be interested in every single subject, but we believe it's important to expose them to a bit of everything regardless. Maybe your classmate just didn't care about math, but enjoyed English and reading, and found that much more engaging. Maybe there was absolutely nothing the math teacher could have done to get that kid to pay attention all the time, even if they were the best teacher in the world.

> he would copy out all the answers from the back of the textbook to his workbook, and he would hand that in.

That's really the big flaw here. If he hadn't been able to do that, his grades would suffer, and someone, whether the teacher or his parents, would have (hopefully!) stepped in to see what was going on, and find a way to curb his game-playing in class. Maybe that would have meant he wasn't allowed to have the laptop out in that particular class until he could demonstrate that he could use it appropriately.

> Teachers are inherently lazy.

I know quite a few teachers, and calling teachers lazy is so mind-blowingly, disrespectfully inaccurate that it's really hard to take your opinions seriously. Sure, in every walk of life you'll find lazy people, but I see no evidence that teachers are on average lazier than people in any other profession. My take on it is that teachers might be on average less lazy than your average human.