Every AppleTV should act as an iBeacon. Perhaps the same should hold true for non-portable Mac models like the iMac, Mac Mini, etc. as stationary beacons.
Portable Apple devices like the iPhone, Apple Watch, etc could be valuable as personal beacons. i.e. HomeKit knows where *I* am because the proximity of *my* watch to a receiving device.
Some existing HomeKit vendors like Elgato would have a leg up here with their devices that already make extensive use of Bluetooth, and could potentially be iBeacons with little more than a firmware update.
Voice assistant based automation is ok for edge cases, but it's far less convenient than using a wall switch. For home automation to be valuable, it has to *improve upon* the light switch. It has to become passive. Knowing that a room is occupied isn't enough; *who* is in the room, and what are their personal preferences?
Are you so sure they don’t allow it?
Develop with iBecons and you'll quickly realize why this fairly obvious idea doesn't pan out in reality.
What's really needed is either:
A. a combination of barrier (in/out) detectors and motion sensors to calculate occupancy, or
B. (Ideal but currently too costly) A ceiling-mounted thermal sensor
I conceived this idea myself about six months ago and wrote Apple requesting iBeam hardware for HomeKit. IBeacons have a real advantage over commands to Siri, or motion sensors. The more user friendly and automatic a smart home becomes then most people should be very receptive to smart homes. Personal preferences could be loaded based upon endless variations time of day, music preferences, light levels, temperature etc etc.