No sense in shouldering the burdensome cost of vehicle ownership if you don't squeeze the maximum utility possible out of it imo. A Tesla battery would keep a home going for quite some time I imagine. IIRC Teslas don't like inverters hooked directly to their 12v batteries and register it as a battery fault, but there exist workarounds: http://www.cafeelectric.com/blog/2020/06/08/inverter-power-connection-1/