When we read written stuff, it's possible to use it in an abstract or a literal way, to store it and to analyze it, and to come to conclusions. Each means of communication has its own advantages and disadvantages, its art and its trash, and can be used and abused. We remember information better when we get it in more than one way. But the modern media are more distant and more easily manipulated. Even today, the most reliable impact comes when someone speaks, in person, from the heart, about matters that can then later be pursued on one's own time through reading, videos, the Web and other resources.
Simple things are easy to apply to daily life.
Eventually, the core that the knowledge was built upon is seen as old hat, 'baby stuff' which we must leave behind as we 'grow'. We forget how much we stand on top of it. Martin Luther's greatest written works were those which he wrote to teach people the core of Christian belief. Yet, I do as a child who is being taught the Catechism. I cannot master it as I wish, but must remain a child and pupil of the catechism, and I do it gladly.