Anyone know what the built-in Bluetooth is for on the new hAP be³ Media?
Probably Home Assistant
Well, they do make the Bluetooth Tracker Tags, I'd imagine they should work on the hAPbe3 (same as KNOT), see
video - https://www.youtube.com/watch?v=YTuZ-VHmqRo
docs - Bluetooth - RouterOS - MikroTik Documentation
So write script to track, or trigger, something, based on presence of the tag nearby.
But it could be passthrough to any container, or /app. The example uses ThingsBoard so that should be possible too.
I think Thread uses same hardware as regular bluetooth. So when they wanted to include Thread and Matter, it make sence to allow use regular bluetooth too. It can make nice smart home hub from this router compatible with wide range of IOT devices.