The big advantage of batteries is the ability to go onto a cheap tariff, such as go, and buy in cheap units which you can use during the day.
So on go you get 4 hours low cost, which you can time dishwasher into as well, and use your cheap rate to charge the batteries.
The other advantage is smoothing, so as your demand and solar output go up and down they smooth that out. So your not for example exporting for 5 minutes then importing because the sun has gone in.
Flux has mixed it up a bit, but in winter your going to want a lot of battery storage or a massive solar array to make it work.
As ever all the ratios between usage, cheap rates, what you can load shift, actual tariffs and prices etc all mean you need to look at your usage. There is no "single best" for solar.
When I played with paybacks I got around 5-6 years for simple solar, or simple batteries. Combined they push they return out longer but they add a lot of flexibility and they are complimentary in effect.
They do not cross into the others payback that much, but they do a bit.
Solar will mainly payback in summer (March-Sept really). Batteries will mainly payback in winter (Sept-March really).
