I don't think that would be a good idea as we all know that in Malaysia there is a lot of robbery and snatch thieves. If every student is allowed to bring a smartphone to school then these robbers will know that every teenager who is walking home from school owns a smartphone in their bags. So this will cause more problems is the country as more robbers will strike. This will cause students to become traumatized, or even can cause death.
Another reason why I strongly disagree is that peer pressure will occur in the school. Now everyone can afford a smartphone. Poor students might feel the need to have a smartphone too and they might steal their parents' money, or steal the smartphone. Some students might be bullied or teased at school because they do not own a smart phone.