The need for a pocket knife depends on your type of job or your hobbies. A computer programmer probably wouldn’t need a pocket knife, but it would be used by someone a construction worker. There are many kinds of pocket knives for different uses. Some have many tools built into them. Tools can be things such as screw drivers, scissors, multiple knife blades, saw blades, or even a spoon. These features may sound ridiculous to some, but can be helpful to others.
My grandfather’s favorite hobby was wood working. He would construct anything in his workshop you could think of. He even built a small rollercoaster for my brother and me when we were kids. Ironically, the most important parts that couldn’t be done by a machine were done by his multi-purpose pocket knife. He used the various knife blades to slice notches for corners, etc. He would use it in more places then one. It even came in handy for tightening a screw in my sunglasses. This prevented one of the eye lenses from falling out. A pocket knife can be such a necessity.