The iPhone could be a Thread border router, but it probably shouldn’t be
The iPhone could control Thread smart home devices faster
Thread could replace Bluetooth as a way to connect peripherals like the Apple Watch to your iPhone
Thread would be fine for most smartwatch uses but not for audio streaming
Thread might just be a bonus radio
Ignoring that the point of Matter (which is so far not happening effectively) is to be a standard shared by all the major providers for smart stuff, this doesn’t mean they’re removing Bluetooth.
It means Bluetooth is a dumpster fire and they’re switching their stuff to use better tech.
Hard to argue with that.