and the fact that it opens quickly and easily by using only one hand is very useful for everyday use. Plus in a car accident that fact may enable you to use it to cut a seat belt and therefore may save your life.
To any real knife fighter, a folding pocket knife (including a switchblade) is at best a second choice. A fixed bladed knife that is double edged would be a far better choice.
One example:
Boker Applegate-Fairbairn I Fighting Knife Of course the black version of this knife would be called an "assault" knife.