Because some devices and browsers have difficulty determining if they're talking to something on the local network or not. And they don't try to guess. So if yo

Because some devices and browsers have difficulty determining if they're talking to something on the local network or not. And they don't try to guess. So if your router requires you to connect via HTTPS, which is a good idea, have fun clicking past a nasty warning and then have nasty icons everywhere telling you that you're not secure. And before you tell me to set up my own local authority and add it to the chain on every device ... common, really? Nobody wants to do that.