Its actually pretty smart if you are a government that want to be in control of everything, think Venezuela, etc. In fact it is so important that history has shown it is one of the very first things done by dictators/rulers/kings when they take over over.
Reading sealed notes being sent from the castle was important. They did not have smart phones, but the strategy is the same. Dictators cannot exist when the people have secret communications.
Ever wonder why America is as fixated on this as China and Russia? Government transparency and personal privacy are both anathema to the ruling elite in all countries. If we don't fight for both, then we will have no freedoms. Our American Founding Fathers knew this.