> Bittorrent is a protocol designed by the company named Bittorrent and there is a large amount of variations and extensions in implementations and clients.

Extensions are in many cases standarized. There's a lot of variations in HTTP as well.

One important thing that's missed is that a magnet link also contains a hash of the torrent file, which points to a specific file. Over HTTP, everyone across the network connection can change the contents of the file and there's no automated way of detecting that.