Do small residential batteries make sense?

Home batteries like the Tesla Powerwall are nice, but what about people who can’t afford them, or renters who aren’t allowed to install them, or people who just don’t want the hassle of dealing with a permit and an electrician? A company called Pila is selling small (1.6 kWh) batteries that simply plug into a normal electrical socket. They can serve as backup for a refrigerator or other appliance in the event of a blackout, but they can also “mesh” with one another to form a network, pair with r...