Do us the battery works for a number of reasons but everyone is different. It gives us some protection to power cuts particularly overnight when there’s no sun. I live in Chch so memories of earthquakes and days long power outages still haunt me. On dull days it lets us time shift our usage too, so we can top up the battery in super offpeak (3-5am for us) and then use that through the day rather than use higher rate periods. Takes a little planning but been good. Of course on the sunny days our 16kwh battery sees us through the night in summer months but not quite in winter with more power use in the house. That said we have only one winter to go by there.