Why does font matter?

Sans serif fonts are made up of mainly straight lines. Sans serif fonts are easier to read in continuous text. On the other hand, serif fonts have short strokes that project from the ends of the main stroke that make up a character. Although serif typefaces often work well in headings and personal stationery, they can be difficult to read in continuous text. They are not desirable for use in a book to be read by persons of all ages and/or persons with visual impairments.