My Pi is used exclusively for a VPN gateway. A VPN isn't a complete solution to privacy, as the VPN providers will admit, but it's a good building block. HTTPS, unfortunately, used to be secure but isn't now, and only encrypts browser traffic (and any other facility which uses HTTPS). Your ISP can (and probably does) break HTTPS with a MITM attack.
A VPN will hide your information from your ISP and make it difficult for trackers to track you by geo-location.