I've frequently (especially outside the US, but even in a major hospital system here in San Francisco) come across WiFi networks that force access web through a MITM proxy. Yes, HTTPS will help me detect it, but if I need to actually get through, a VPN is helpful.

"bank info" in this case being anything from logging in to check my balance, pay bills or even contact them via their secure messaging because I'm disputing a transaction.

It doesn't eliminate all threats, but I'm not a secret agent ninja that needs 100% hardened communications. I just need a modicum of assurance.