because they are easy on the mind. They are used to postpone the time when the mind has to engage the difficult tasks (homeworks.) Since there is not enough time left, the mind has to rush through the suffering, with an outcome that can be blamed on the lack of time.
A tough situation.
Next time when you see him wandering, ask: "Do you want to be a slave?" If he answers "No," then say: "Don't act like one."
If he does not answer, you say: "You want to be master of your own life. Have control over things and not let things control you. Otherwise, you ARE a slave, begging the screen to feed you."