Overlay keyboards have several advantages over conventional keyboards or mice. They do not require memorization of shortcut keys (i.e. F5, Alt+S, etc.) nor do they require a great deal of fine motor control, making them ideal for people who have difficulty using a conventional keyboard. Overlay keyboards are easy to clean, and resistant to spills or dust. The ability to change overlay sheets also makes it easy for a single overlay keyboard to have several different uses.
Overlay keyboards are probably most often found in fast food restaurants, where they reduce the amount of time required to enter items. Overlay keyboards are also used in education, especially at the primary level. They can also be used by disabled people who have sensory or motor control difficulties.12
P. Blenkhorn, "Switch, overlay keyboard and touch screen software for children and adults with profound and multiple disabilities", Feb. 24, 1998, accessed Sept. 22, 2007 http://www.dinf.ne.jp/doc/english/Us_Eu/conf/csun_98/csun98_014.html ↩
"Everything You Need to Know about Overlay Keyboards", accessed 29 July 2009 http://www.overlaykeyboard.com ↩