As far as security is concerned HTTPS and a VPN do the same thing. That is provide an end-to-end encrypted session. The only added benefits of a VPN are that all protocols go over the VPN are encrypted and owner and other users of the same access point (if you're on a public network) can not see any of your traffic safe for that you are connecting to your VPN provider (DNS, IP destination). This adds a measure of privacy assuming you can trust the VPN operator.