P2P downloads of OS updates - Could this be useful for the Trisquel project?

I vaguely remember some discussion of a system that would allow Debian users to share updates with each other, instead of always having to hit the repo servers. From what I remember the idea was to set it up in such a way that the UX is pretty similar, but the update and upgrade commands would use search across and download from a P2P network of other users' systems, instead of (or as well as) from the repo servers/ mirrors.

Does anyone know if such a system is up and running for Debian? If so, would it be possible to set up a similar system for Trisquel, to allow for a massive increase in the number of Trisquel users, without putting massively increased pressure on the servers running repo mirrors?

I did a bit of a web search and found these:
https://wiki.debian.org/DebTorrent
http://www.camrdale.org/apt-p2p/

But I'm wondering if anyone knows if one of these (or something else) has made it from proof-of-concept to regularly use in production, and if not, why not?

There's some interesting discussion of the potential pros and cons in a thead on /r/linux, but they mostly focus on the benefits (or lack there-of) for end users, rather than for those currently running repo mirrors:
https://www.reddit.com/r/linux/comments/2zdysl/why_linux_distros_doesnt_use_bittorrentlike_p2p/