Yeah, I ended up using an old mac mini for my Home Assistant needs. It draws a whopping 7W from the wall at idle (and it's near always idle), but the price of a new RPi is the same as 13k hours of electric usage for this.
Using whatever compute you have sitting in a drawer usually makes the most sense (including an old phone).
Using whatever compute you have sitting in a drawer usually makes the most sense (including an old phone).