It depends on a number of things
First, we would need two, unless you expect me to leave my wife without power when I go to work. Second and third, it would depend on how long it could power the house and how much it would cost. My last serious power outage lasted almost 4 days, and I suspect that the car would not last that long. Additionally, I can get the appropriately-sized generator fueled with natural gas installed for around $5,000. I've never had the gas go out. I suspect that the car would not be equal to the task.