Bidirectional charging in and of itself is an existing technology, albeit one that required industrial-sized charging stations and normally only used in large vehicle fleets. Wallbox has taken that technology and miniaturized it, shrinking the charging system into a form factor that fits in your house. The Quasar is Level 2 charger, meaning it pumps 240 volts, and is compatible with vehicles leveraging Type 1 connectors as well as the CHAdeMO style that Tesla prefers.
Since your electric vehicle is essentially a giant battery mounted on wheels, it can easily serve as an emergency or alternative power supply for your home -- assuming you can manage to extract it from the vehicle. And that's exactly what the Quasar does. Users can pull charge from the car and use it to run household appliances (even washers and dryers), thereby reducing their draw from the local grid. This is especially helpful for people living in areas with variable electricity pricing -- charge up the car when prices are low, and discharge it for household purposes (or sell it back to your utility) when prices are high.
Unfortunately, only the Nissan Leaf and the Mitsubishi Outlander are currently capable of utilizing bidirectional charging but bidirectional charging has the potential to revolutionize both the EV and renewable energy industries, should it gain widespread adoption.