Hybrid battery systems can give you the benefits found in both on-grid & off-grid systems.
The extra solar power that you don’t use gets stored in the battery for later use instead of being sold back to your energy retailer. That means you can drastically reduce the amount of power you are buying from the grid. Once the battery has reached 100% state of charge your excess solar power will still be sold back to the grid to give you credit on your power bill. In the case of black outs you will seamlessly change over to your battery power supply with dedicated power & lighting circuits.
Batteries are not a new technology however charging them from solar power & suppling energy to large applications is highly technical stuff. Thats why insist on the industries leading technology.