It'll be interesting to see how this is pitched and what it's price point is... I'm still not convinced that energy arbitrage is profitable enough for individual homes given the current cost of the storage.
For one example among many: if grid frequency drops below its nominal 60Hz, that indicates electricity demand exceeds supply, and the kilotons of spinning iron and copper in the generators that supply the grid are slowing down as they contribute rotational kinetic energy to meet demand. Grid management options for this type of demand/supply mismatch include calling for increased output from generators that aren't already at their max, engaging idle-output (but phase synchronized) spinning reserve generators, and buying power from contiguous grids.
Power sold under these circumstances can be priced at large multiples of base rates (like net metering rates) because of its high value in stabilizing the grid.
Smart grid infrastructure (communications, controllers, bidirectional inverters, etc) will allow grid managers (or localized intelligent algorithms) to draw on residential energy storage for ancillary services. These services should bring residential participants much higher returns than existing simple and not very lucrative net metering schedules. However, I imagine there will be significant legal combat before resident owners of distributed storage are allowed to recover market rates for their ancillary service contributions.
Anyway, if it can clearly save me money and is not incredibly expensive up-front, I'll likely get one. Even if you actively conserve, electricity is decently expensive over the long run.
Why would they? I would have thought it's no different from any other household appliance.