I would say very simply that a tsuba makes you lazy. Learning how to protect your hands and knuckles etc. is all part of the training.
I would even extend this to any form of padding or armour meaning the down side is you get complacent and thus feel that part of your body is protected.
Sorry to diasgree with you here.Using a tsuba is using common sense.How do you arrive at the conclusion that it makes you lazy and complacent?I agree that you have to learn how to protect your hands etc, but while your students are learning this process do you advocate a policy wherby a junior student get his/her knuckles wacked?I think not -hence the use of the tsuba. cheers,Joe.