That's not exactly what I was writing about: if you distribute the file directly and have it distributed through the system, yes; but people downloading have no assurance that any file named X is the same file as X. You see what I mean? If you don't know the author, and there's no trust mechanism that currently allows you to "know" an author, then you don't know whether a file originated from the author who is distributing it or not.
Someone could take our book PDF, add a virus, bundle it up, and name it "Real_World_Adobe_GoLive_6.pdf.exe".
BitTorrent isn't an excellent choice at the moment for the reasons I cited: people can be fired, suspended, or expelled for using ANY P2P in many places, and our likely reader base wouldn't use a program like BitTorrent for reasons of obscurity (they're not in that community of people who know what P2P is) or job security.