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.
It’s good even if you don’t do batteries. For one, get a large electric hot water heater. That’s effectively storage for a lot of the energy you’ll take in. If you play it right, you may never heat water off grid power, saving you a lot.
Plus you can sell your excess to the grid during the day and pull in grid power at night. It should even out to an extremely low electricity bill every month.