In simple terms, split tunneling lets you choose which apps or sites use the protection of a VPN and which don't. While VPNs are worth using for extra security and privacy online—foiling trackers, spoofing your location, and stopping your internet provider from seeing your browsing—they do by their nature come with some compromises in speed. If, for example, you want to get the fastest possible speeds with your online games, you might want to leave your games outside of the VPN's remit.