Offset sheetfed printing presses would be nothing without ink. It's the reason the press exists. Good print starts with good ink that performs well in the press and in the press room and printing ink can be one of the largest indicators of overall print quality.
Inks can come in many varieties beyond just the color. Inks can come in different tack and finish. Inks can also come with different additives that can help them to dry more quickly. Ink technology in the 21st century is quite advanced and as time goes on we are sure to see very interesting inks in the future.