1 watt savings idle? .72 kwh a month? in my area that's about 5₵ , even in california that's 40₵ / month / device ?
Are 1000-instance Pi arrays common? i can think of 100 better ways to get that amount of computing resources.
The existence of commodity, well-documented, well-supported SBCs offering more computing in less power is exciting.
(Also, using less power means you can put it in more places without worrying about getting rid of the heat, or can go longer before throttling).
Honestly, it feels like you're trying to prove me wrong about my one case. Power consumption and heat dissipation matter. The pi is rarely the lowest power path one could use to do computing, and it isn't the highest performance, either... but using less power and having more performance makes it suitable for more things (obviously).