A torrent file stores metadata used for BitTorrent. It is defined in the BitTorrent specification. Simply, a torrent is data about a target file, though it contains no information about the content of the file. The only data that the torrent holds is information about the location of different pieces of the target file. it's often used to make uploading files easier!
and torrents are safe but you should know from where you download the torrent file like www.thepiratebay.org and yes what you Wrote is possible cause after extracting the torrent file you can burn the game on the DVD and play it on your PS3 and in some countries it's legal and in other countries it's illegal!

Some Torrent Sites:

www.torrentz.eu
www.thepiratebay.org