I believed that without having the skills to utilize a knife, your self-defense training is incomplete. This is a new era and many times a knife is deployed in the onset, in the middle of or at the finish of a physical attack/assault. It is imperative to have an equalizer in combat and the knife is the most important equalizer you can have. The knife removes the concern of how big they are or how strong they are as the knife equalizes the playing field to give you the advantage in a survival situation.
Knives are legal to carry and they are easily accessible which makes this a very real threat to consider.
We must develop the skills to read a knife attack as its coming in otherwise we may not be successful in defending the attack. The person with a knife has a significant advantage to the opposing party! By learning how to use a knife, we also develop the skills to read a knife attack which is critical in tactical knife fighting as well as open hand -vs- knife.