There are many uses of OTF automatic knives, including for any emergency exits in vehicles, for self-defense in case of an attack, at the dining table and when camping. They are primarily for military, police, and EMT duty says BLADEHQ.
At the dining table, the knife serves the purpose of cutting food. When camping, it serves many purposes, including being a weapon, cutting tool and opening a soda bottle when thirsty. The knives open with the simple press of a button or pull of a lever, says Wikipedia.org. Their prices range from $7.50 to more than $7,500 on BLADEHQ, as of 2015.