OpenType fonts provide several advantages over traditional fonts:
1) They contain thousands of characters like ligatures and alternate letter forms rather than just 220, reducing the need to use multiple fonts.
2) Their larger character sets mean less time switching between companion fonts to find special characters.
3) They can automatically apply ligatures, swash characters, and other typographic features without memorizing keyboard shortcuts.
4) As single "smart fonts" they understand language and can support multiple languages in a single file usable on all major platforms.