Quote Originally Posted by Rater202 View Post
If you only make one cut, it won't stick. The severed fibers will reattach.

The in-universe reasons aren't explained... But we're talking about an anime where a girl is using giant scissors to fight evil clothes, so there's your doyalist answer.

And honestly the why isn't necessary any more than you need to know why you can't just stab a vampire's heart with a dagger, you need a wooden stake.
I mean, its the difference between "Shadow can cast Chaos Control and brute force his way to victory" and "Shadow only wins if they give him the macguffin sword he needs to affect her at all." So it seems kind of important.