"How good is it?"
A practitioner (not me) was doing the kata called "batto", slipped and ran the tip through his upper arm (not just into but through).
His doctor examined the wound and any damage the vintage sword might have done to the surrounding tissue. The cut was so scalpel neat, he just pressed the edges together and wrapped on a bandage to hold them steady. It healed smooth.
What comes to mind;
"Why do a kata with a razor-sharp sword?"