cause equipment should be protected somehow in academy i assume
and it finally lets protect your enchantments in a way it shifts the strength from equipment a bit into the direction of enchantments, cause pre academy a nullify protected your equipment, but now with crumble you need a nullify and a ward to protect it against dissolve and crumble and will never be action efficient. but you can protect your forcefield better for enchantments
and it had always been possible: decoy, just there was no point in it, btu you could do it