The volume of the transfiguration makes it negligibly quick; nanotubes have the highest tensile strength of any material and they were not lone tubes, but braided; I'm fairly sure spotting a braided nanowire in the dark is nearly impossible; and the tension transfiguration is what made the slicing consistent. How exactly is it not practical?
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 114, and also, as a special case due to the exceptionally close posting times, chapter 115.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)