“When you use HTTPS or SSL, your web browsing traffic is encrypted. When you use a VPN, all of your traffic is encrypted (usually). Sometimes even with HTTPS and VPNs in play, DNS requests—or the way your computer translates “lifehacker.com” into numbers that your computer understands, like “199.27.72.192,” are completely unencrypted, leaving you open to spoofing and man-in-the-middle attacks. DNSCrypt can lock that down.”
_{Lifehacker: How to Boost Your Internet Security with DNSCrypt}