When we planned our system last year (in Texas, that only has a few options for selling electricity back to the grid), we made our estimates based on the savings from a traditional electricity plan (fixed price per KWh). We planned our system to produce around 50% of our annual electricity usage (we're doing better than that).
After operating the system for 5 months, based on actual usage, we switched to a "Free Nights" plan, and are doing even better than we would under a net metering plan, because with solar and PowerWalls, we're able to significantly reduce the amount of grid power used during the day, and by scheduling EV charging overnight, we're able to pull 80% of our electricity from the grid for free.
We're not expecting utilities will eventually exclude homes with solar/energy storage from their Free Nights plans - but until that happens, even if net metering is available in an area, if there are Free Nights plans, homes with solar/energy storage may save more under those plans than relying on net metering.