The main usefulness of Bittorrent protocol is that you can transfer very large files using it with ease. It is a cost effective solution to transferring large files. It uses the bandwidth of a user to send files to another user.
It is like moving files from one computer to another but using a Internet based system. The speed at which the files are transfered depend on the speed of the Internet connection of the user who is giving the file to another user.
If you try to send large data via a normal server, it will cost a lot since web hosting isn't cheap. But if you send it using torrent, it is much easier. You don't have to buy any subscriptions to cloud services to send it using just a torrent client.
Also, Bittorent is much easier than other file transfer solutions. One of the most commonly used torrent client is uTorrent. It is a very nice GUI for end users.
The benefits of torrent have made it one of the best choices for distributing high amounts of files. For example, archive.org uses this BitTorrent protocol to let people download its files.