Three years ago, my new home came with smart features such as a connected front door lock and thermostat and a wall panel with a sim connected to alarm.com. The intro period ran out, and I didn't want to pay anything ongoing, so I bought a z-wave usb controller and set up HomeAssistant on my old Pi2. With some effort to get everything working in docker with a cloudflare tunnel, I am back to being able to monitor and control my smart home from anywhere.

I'm not feeling compelled to get a more powerful pi. In fact, I'd be more inclined to buy the pi zero or several of them, but they were always impossible to find in stock when I was interested.