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
Pretty much everything produced Eve (besides their cameras) and Nanoleaf is Thread. They were once only available for the Apple ecosystem but since the Matter standards were released they have been venturing out.