There are a number of reasons you might want to use a VPN for torrenting.
DCMA notices, fines or prosecution
Preventing yourself from being served a DCMA (The Digital Millennium Copyright Act is a United States copyright law) notice is one of the major reasons to use a VPN service for torrenting files. You may be forwarded the notices from your ISP (Internet Service Provider) at the behest of copyright enforcement trolls or RightsCorp.
So, using a VPN services saves you from lawyers who could take you to court for fines and damages.
Security & Privacy
Students are also served copyright infringement notices by their university/college IT departments. One recent incident involved Bristol University’s student banned from using university’s WiFi network for using torrent site to download a copy of Chicken Run. Had she used a VPN service, the situation could have been avoided. To secure your digital footprints when using torrenting sites or p2p streaming software like Popcorntime use a VPN service. Before making a choice it’s recommended you read some reviews of the most secure VPN for torrents.
Better Internet Speed via dedicated servers of Torrent providers
Some VPN service providers have dedicated torrent servers to avoid slow internet speed issue (which is normally associated with using VPNs). You can locate one of more of such VPN providers and enjoy a high-speed torrent download.
Privacy-minded people are interested in maintaining their anonymity over the internet. Everyone has his/her naughty moments and you don’t want to get tracked afterwards downloading a torrent file. This is a sample reason people use VPNs for even carrying out their usual online activities.
Torrenting needs additional protection as different stakeholders are on the watch-out for detecting IP addresses from where torrenting is executed.
Accessing geo-restricted content
Some of the premier content providers (like HBO and Netflix) have geo-restricted their content (films, reality shows, and television shows). Using a VPN lets you bypass these restrictions and watch the geo-restricted content without having to actually be in that country.
Saving you from DCMA notices, accessing geo-restricted content, better torrenting speed from specific VPN providers, and maintaining anonymity over the internet, and ensuring digital security and privacy are the top five reasons that using a VPN makes sense for torrenting.