...in both cases the objective is a secure encrypted connection

I should have added 'authenticated'. The user normally needs a password, certificate, security-code-generator, or similar to establish the connection, so the remote server knows who's connected.

So different from https, where the data is encrypted but anyone can connect. And your ISP can see that you're connecting to mudcat but not read your posts. Over a VPN the ISP can only see the address of the VPN.