Yes, completely useless
Unlikely. Even the DIY Zwave modules typically focus on providing relays or ways to attach sensors only. They are not going to work as a generic communications protocol to drive a display.
The power consumption of the displays is awesome and the readability from angles and at day is unbeatable. I also started playing around with the 2.13" epaper to display room temperature/humidity, date and weather info. As we sometimes have drops on the inside of our windows during winter, it should indicate when humidity is too high (red). All linked to OH by Wemos D1 mini (with sensors) and MQTT. Worked well but to get WAF I need to get a nicer finish (case) which I didn’t have time for, yet.
Ouch. Thanks for showing us!