Complex sentence: The early 21st century has seen noticeable growth in stylus-and touch-operated interfaces, making the use of on-screen keyboards operated by pointing devices (mouse, stylus, or finger) more important.
Split into simpler sentences: The early 21st century has seen marked growth in stylus-and touch-operated interfaces. So the use of on-screen keyboards operated by pointing devices (mouse, stylus, or finger) has become more important.