I hope these new thread devices still work without an Internet connection. The best thing about Zigbee is that it's guaranteed to be fully local, but according to the thread standard, border routers should allow Internet access. With OTBR it's at least possible to disable NAT64, but I wonder how many devices will refuse to work if they can't phone home or offer only basic functionality via Matter and require the use of their own cloud based app to access the full feature set.