I do see the point here. Students do need to learn to think, not just regurgitate. But, allowing phones in class is more likely to be a distraction to the student using it, and possibly other students as well. Young kids especially are still learning how to learn, and ensuring that students learn to think and work individually is more important than making it like the "real world", for the same reasons we don't kick our child out of the house if he doesn't finish all his chores (even though in the real world, an adult may lose his job if he doesn't perform adequately).
Making use of phones part of classroom activities is a problem anyway, because not every student has a phone, and not every student that does have a phone has one with the same capabilities. Some parents decide their kids don't need cell phones, and some parents can't afford to give their kids a phone.
Really, cell phone use in the classroom should not be allowed, and if the rule is broken, the phone sits on top of the teacher's desk for the rest of the day/period (so the student can see clearly that the teacher is not "snooping" in it), and the infraction documented. Parents should be notified at the beginning of the school year that phone use in the classroom is not allowed, and what the consequences are, and then those consequences should be applied. Maybe after so many infractions, the phone is not given back to the student, but the parent has to come get it, for example. You don't have to stop the kid from having the phone in his possession, but if it makes noise, or is brought out of the pocket/bag/whatever during class, then there's a problem.