Many adults have forgotten the struggle they went through to learn to read and write, so it can be difficult for them to realize how important these skills are in their everyday lives. Icons today have replaced much of the words people depended upon previously, but that does not negate the need to learn. Reading and writing skills for life are an important part of any basic education, and having them gives a person a reasonable ability to be able to navigate in the majority of situations they will face.
Going through life illiterate is considered a handicap in many modern societies, so teaching these skills to each person matters. Those who do not have these abilities will struggle when faced with a situation out of their normal experience, and they can become overly dependent upon others. Adults with good reading and writing skills have many more avenues to communicate with others, and they have a greater ability to be able to help themselves when unplanned situations occur.