When I look at topics about HA Bluetooth, the vast majority discuss dongles.
As we know, HA Yellow comes with built-in Bluetooth. Yellow comes with a SiLabs MGM210P, which is based on the EFR32MG21, that has Zigbee, OpenThread, Bluetooth 5.x, and multi-protocol connectivity.
ZigBee is very easy to access on the Yellow. Crickets with internal Bluetooth and the other connectivity. There is this thread that devolves into dongles and other topics: Bluetooth - Yellow Box - Iphone Location
Is lack of available Bluetooth integrations because the MGM210P is unique to Yellow?
Is it because only one connectivity can be used at a time and ZigBee is preferred?
The Yellow product page makes no mention of built-in Bluetooth. Only Zigbee OR Thread. There was an experimental driver to do Zigbee AND Thread, but the stability was apparently so bad they actively tell people not to try it. It’s possible that chip technically does Bluetooth, but I don’t think the Yellow uses it.
If you want Bluetooth on a Yellow, I believe you either need to get a CM4 module with built-in Bluetooth (that’s what I did) OR you have to get a Bluetooth dongle.
Given they could never get Thread and Zigbee working using the same radio, I can’t imagine getting Bluetooth working with one or both of them. At some point you have to decide what you’re going to have a particular radio doing. Yes, the SOC has the capability for Thread, Zigbee, and Bluetooth, but that’s most likely an artifact of the fact that those three all use basically the same frequency range more than an actual ability to use them all at the same time.