Also see Chip / Matter support (including Thread)
Home Assistant Yellow contains a UART/GPIO radio module based on the same type of Silicon Labs EFR32MG21 SoC that the Home Assistant SkyConnect USB Stick is based on, so yes they will be able to do the exact same thing, however, I believe that the Thread (and Matter over Thread) part is not ready for end-users as of yet, which I think is the reason why the Home Assistant SkyConnect USB Stick](Home Assistant SkyConnect - official radio USB dongle will be compatible with both Zigbee and OpenThread (including Matter/CHIP over Thread)) has been made available for purchase as of yet. That is, right now I believe that the end-users who have already received their Home Assistant Yellow can only use the Zigbee part as of yet and not yet the Thread part? There are some development discussions between the developers here → https://github.com/zigpy/zigpy/discussions/894