If you're already committed to owning a bigass $100K electric truck this is an inarguably awesome side benefit. It's a truck, so... you have a few hundred miles of range. Slightly better than "down the street."

But for the other 99.99% of humanity, there are certainly more cost-effective ways. A portable power station and solar panels are probably the better move unless you have some really massive power needs.

(Admittedly, a nuclear winter reduces the effectiveness of those solar panels somewhat)