While you are reading this you should think about how effortlessly you are doing so. And by being able to you are have (I hope) learnt something valuable. At least we, as human beings, have connected.
According to Derrida, writing is marked by absence. what he means by this is that the containers we call words do not really have a stable and full meaning. Saussure pointed out the arbitrariness of the signifier and the signified to mean as much.
Nonetheless words have meaning. Otherwise, all that we say, all that try to convey with words would be useless and empty gestures.
Writing serves as memory. Before things were committed to paper (velum or whatever other material) we learnt things by rote, things were committed to memory. The Buddha, Jesus and Socrates all left nothing in writing, but those who followed did write about them, for better or worse. Whichever way, writing is important. And printing perfected reiteratability. Without writing the internet perhaps would be relying on images alone. And while a picture may be worth a thousand words I wouldn’t trade it in for a single one of these words here.
No, literacy empowers. How else would I have a chance to know about the history of China, the philosophy of Kant and Wittgenstein, read the latest news, know that the dinner is in the microwave oven, or that today is International Literacy Day.