Weapons are some studied extensively in the martial arts. sometimes this training is grounded in reality but most often it isn't. What then is the value of studying weapons in the martial arts? Well firstly it relieves boredom for studies and instructors alike, techniques are techniques but put a weapon in an opponents hand and suddenly the training is a whole lot more real, suddenly there is focus and adrenaline to deal with. Secondly weapons are a natural extension of your body, in the martial arts extending your mind and focus beyond your body, beyond and through your opponent are vital - weapons can provide all of these things. Thirdly in many arts (in particular aikido) the origins of the arts are in armed combat, its a poor samurai who was wandering about weapons less. Thus weapons practice allows the study of the arts in the traditional perspective.
Why then is the training removed often from reality, why is the X block still taught as a knife defence? Interesting question the latter and the subject of much debate. However the former its worth remembering that the weapons arts are inherited from long ago often and rarely subjected to the battlefield today so some dilution is natural, some modification of the techniques is important for safety and sometimes the techniques assume the exponent is wearing full body armour. Whilst I have had the opportunity to practice weapons as a part of aikido its only through going outside my school that I was able to question some of the practices, reevaluate and appreciate them for their historical consequences.