A. Are the costs associated with the batteries included in $1/watt — I don’t think so.
B. That would work well in warm climates.
A. Run off batteries B. Run off the grid, when power is cheaper.
Bingo.
With net-metering essentially the grid IS the battery as long as the total solar power supplied is less than the grid draw. And there is a long way to go before that happens.
Similarly with net metering a battery in every home is a battery in the grid.
The caveat of course is the various "surcharges," taxes, add-ons, etc. which an electric company, or government, can impose to screw it all. That is, if the energy you sell back is not at the same price you buy.