Are martial arts hard knives and soft knives used for the same purpose?

Hard knives and soft knives are different, just like sticks and whips, as for the price I don't know. When you say use, it depends on what you mean, the original main use of the knife is for self-defense, if it is based on this statement, they have the same use. Only the soft knives are not well practiced, the hardest is a very long one called the Burmese knife, which is very soft.