`First, so that the device can protect itself from malicious sites it can provide a set of origins that are allowed to connect to it.`

Sounds kinda DRM-ey. The CORS system works because the owner of a URL is the person who can attach headers to responses. That doesn't sound the same in this case, as the owner of a device is the person who owns it, not the manufacturer who decides what metadata it broadcasts (though obviously working out what the UX should be is a hard problem)