Correct. Unlike zigbee and zwave Matter does not define a single communication technique.
It can be used with thread, or over a standard ~~tco~~ TCP IP network.
Typically, Matter devices will support either thread or WiFi, but there's no definite distinction to Matter itself.
If you also want to use Matter over Thread devices, you will need a thread dongle. The ZBT-1 can do either thread OR zigbee but not both at once.
In fact, the biggest issue I see with Matter is that there's no real easy way to tell if the device uses WiFi or thread.
There are a lot of Matter devices out there now, but only a few use the Thread protocol.
There's so much more room out there than there is here on this finite planet.