I regularly use BitTorrent to download and re-upload (usually by a factor of at least 3) the Ubuntu distros and the BSD releases, to help make them readily available. I have a static IP DSL and do not use much of my up-load bandwidth, so running Deluge in the background making 3 or 4 ISO files available to others who might want them, seems to me to be a good use of my machine and my 'Net connection.
Among our group, I have become the keeper of the ISO files, so whenever anyone wants a CD, I simply burn one. My CD burner does a thorough check of the disk, so I'm sure a disk is good before I give it away.
I use P2P file sharing in a legally OK manner in part to hold that option open for everyone, as there are ISPs who would completely block BitTorrent because they believe ANY file(s) distributed via BitTorrent are, by definition, pirated software. I am out to prove them wrong. And, the fact that BitTorrent provides error free copies is a nice plus.