The problem is that a lot of (admittedly overstretched) parents use the phone as a pacifier and don't monitor use much if at all.
Tommy's being a little shit? Give him the phone so he's distracted.
Of course, if little Tommy's never learnt to deal with being bored, keeping quiet for half an hour, and never learnt to concentrate for longer than the length of a tiktok video, he's going to have trouble adapting to education.
Burn old batteries in the fireplace!