It's very confusing with a new Zigbee standard when I thought it was being replaced with Thread

And from the same organization that co-designed and promotes Matter.

Personally, I'm very happy that Zigbee continues to be developed. I am not very enthusiastic about everything being IP addressable (even if it is just ULA) and the convoluted Thread flow where a bunch of border routers require you to initiate the pairing with a phone over BLE to hand it over to the router. I have an Eve Energy Thread + Matter plug and it requires many takes to pair it correctly. Most Zigbee devices are just a matter of permitting join on your coordinator and holding/pressing the pairing button on the device.

I wish that Apple and Google would just add a Zigbee coordinator (or just leave home automation to others) and put some effort into supporting a wide variety of devices rather than trying to disrupt a perfectly working standard. They often cannot even bother implementing the latest Matter spec timely.