Choose body type for sustained reading, not just for how it looks on a single screen. Letter shapes, spacing, line length and paper color all affect comfort. Decorative type is best reserved for short headings or accents where it will not slow comprehension.
Review a printed sample at actual size and test it with readers when possible. Older audiences may benefit from slightly larger text and generous leading. Consistent typography gives a book a polished identity while helping readers focus on the author’s words.