It's not that different. It might be easier than your average "pwn" and might not require root access, but this is only my hypothesis based on what's written in TFA.
Maybe an issue here is WebSerial, as HCI comes over a serial port device. I believe the OS should block access to the serial device once the host driver takes it as a Bluetooth adapter though.
IIRC, that restriction was removed.
It's an IOT device. Everything's running as root.