You know MITM an https website is child’s play, right? If you’re inputting your password on a network you don’t trust you’re doomed. SSL certificates are worthless because they can be easily forged by anyone pretending to be the site as long as they’re between you and the actual site, which they need to be to MITM.
VPN and HTTPS solve different issues, and are better when used together. Most of the time you don’t need a VPN because you trust your home network and ISP, but if you’re using a public access point https does not replace a VPN.