Do you mean that you don’t need a way to verify the routers identity on the local network because it is already protected by a password?

Firstly, I don’t think that’s true because you add a lot of sketchy and unknown devices to your network over time (guests, streaming stick, computer with preinstalled OS…) so I wouldn’t trust every device in my WiFi.

And also, if you do trust your network, you don’t really need https inside it, right?