I practice Hema as well as my karate. this is a common question and one that is a good one. I think and this is my opinion but using a weapon be it sword or staff will train the body and mind differently than using just fist and feet. You say i will never use it, but you will even in unarmed. Having learned to use a weapon will make you better understand how to move relaxed as trying to muscle a sword is like running in pudding. this will translate to everything even house work. in a way weapons training is like using a weight vest/bracelets, you have added weight where there was none this will effect how you move and your balance. Finally i think you can translate the sword to a stick, the slashes even with a stick will hurt and a good thrust is a great way to attack.