It is the duty and job of the developers to reach out to the user in various ways to download the ROMs. They can do so by uploading it to different file transfer protocols, attach the file to their own XDA thread. Torrents are the new way to increase their reach to the users which they regard as their new option as the government is not so gentle to keep these file upload sites up and running.
Torrents are synonym with piracy in layman terms, but developers at XDA such as carnagenX is strict enough to post a tracker for developers. The secure thing about this tracker is that only the developers will be allowed to post the torrents. Although the upload arena has confined to limited space but still it is safe to assume that the tracker will be secure from pirated uploads.
To get more information about Bitdroid, Visit the original thread.