The main threat to your privacy induced by BitTorrent lies in your IP address being stored in the instance's BitTorrent tracker as long as you download or watch the video.
The video quota only takes into account the size of <x id="START_TAG_STRONG" ctype="x-strong" equiv-text="<strong>"/>uploaded<x id="CLOSE_TAG_STRONG" ctype="x-strong" equiv-text="</strong>"/> videos, not transcoded files or user export archives (which may contain video files).
The worst-case scenario of an average person spying on their friends is quite unlikely. There are much more effective ways to get that kind of information.