From TFA:

That means households can charge their EV when power is cheap

If electricity is always the same price it would not make any sense unless:

That means households can charge their EV when power is cheap, and either use the stored energy themselves at peak times, or sell any surplus back when the price is high.

or maybe:

A charged EV with a two-way system could also help a household to get through power outages caused by storms or other severe weather.

I will also add that I have been thinking about getting an EV and installing solar panels. My power company does not buy back excess electricity (they give a rebate on the electricity I buy from them with any excess). It is a little of a special case as I only drive maybe 2 or 3 times in an average week. Having something that can serve as a charger for the car and also power the house at night might be nice.