Or simply for hiding your IP when torrenting. Bouncing things off of your home network is fine for hiding your activity when using public WiFi… But it won’t do a goddamned thing to protect you when you’re torrenting at home. Plenty of people have ISPs and/or governments that care a lot about what they torrent, so using a VPN is a very easy way to avoid those bright red “we’re going to shut off your service if you keep torrenting. Also, we gave your IP to the authorities and you’re being sued” letters.