In addition to the sibling comment, I'll add that I don't want to have think about whether my EV is at 100% or 30% despite it being connected to the charger for the last 12 hours since I got home from work the day before.
Also, existing EV owners don't have an EV <> Household bidirectional interface connected, and I'm not aware of any serious vehicle manufacturers claiming they will do this. Probably because if the battery has an X kilometer / Y year warranty, how does using it as a household power reserve affect that warranty?