Emergency Backup
Store energy for unforeseen circumstances outside your control or when you need that sudden boost of energy for your house when the grid throttles power.
Grid friendly.
Use your storage to reduce the load on the grid at peak times, which also happens to be when power is most expensive, so you can use the energy stored when electricity is cheaper.
Accelerating Renewables
The biggest problem with renewables is that the source is not constant and needs to be stored. With energy storage in your house, your house can help accelerate the switch to renewable energy as it can charge during the day with surplus energy from sources like Solar.