I'd like to use z-wave but as an Australian we have different allowed frequency bands (specifically the USA-market gear uses frequencies that are reserved for telecom use over here, and anything that can interfere with the ability to call emergency services is Very Illegal), and thus the few devices that get built supporting the AU rf bands are overly expensive due to the (lack of) economy of scale.

As a result my home automation stack is a mix of zigbee, Matter (over both Wifi and Thread), and just plain WiFi. All of which uses the 2.4Ghz (and 5Ghz but mostly 2.4 for the IoT stuff) ISM band(s) and is thus cheap and plentiful.

Not sure how many other regions suffer the same issues, but I suspect that z-wave will be outcompeted by the more modern alternatives in the coming years.

/rant