Combat with Steel Weapons in full Armour is one of the only ways to see if a technique really works without killing your opponent. It is essential when practicing martial arts to create as realistic of an environment as possible. This helps to separate out what it real from what is not. Many schools teach techniques that can never be used full speed, full force with full intent on opponents, therefore most are worthless when it comes to an actual conflict.
The use of protective armour allows practitioners to get as close as possible to an actual combat situation without damaging each other too much. This is essential to learning how to strike, move, target and fight as if it were real.