But when the vehicle is connected, the user is typically at home. So there's a convenient relation there.
House power consumption is random because it's not designed to be predictable. It's trivial to have a washing machine and heating that prioritize energy consumption whenever the EV is connected, or grid energy is affordable.
Unless you have more than one person in the house…
But in general, yeah, when you _need_ the battery, maybe you just need to figure out that you don't need to drive that day/hour.
The other advantage of a car, is that it would allow you to bring in power "from the outside", go to somewhere where the grid is still working, charge up, then come back. Of course, you'd hope to be back on power before this was needed!
House power consumption is random because it's not designed to be predictable. It's trivial to have a washing machine and heating that prioritize energy consumption whenever the EV is connected, or grid energy is affordable.