That ideas is (was?) the solution to keep a large grid powered with massive renewables who make grid loads vary much in very little time, something NO fossil/nuclear power plant can cope, so something that provoke continuous blackouts because when the Sun rise suddenly the "classic" power plant load fall and they can't reduce power quickly enough so the frequency skyrocket and they disconnect. Similarly when clouds pass or Sun goes down the inverse (a sudden peak) provoke a quick drop in frequency with equal effects, instead of power plants entire part of distribution network disconnect suddenly to reduce the load and the the frequency. Batteries are quick enough to cope. So the idea was: when the Sun goes up the sudden drop in load will be absorbed by cars who start charging full power than slowly reduce to give times to classic PP lower their production, when the Sun goes down they discharge to the grid for a little while with the similar target. Since batteries do not last longer and cost a fortune EVs are a way to shift the costs to the users.
If you have p.v. at home you have to face big capex BUT you can lower opex lowering high electricity price using your p.v. and car, or so to speak if you help the transition you get paid back. If you can't you simply suffer higher tariff getting equally more poor from another way. The wealthy became poor due to high investments, the less wealthy due to the sky high cost of living. And you know the classic WEF/2030 https://youtu.be/Hx3DhoLFO4s vision.
Casually people are a bit dumb en-masse, as Gustave Le Bon and Eduard Bernays wrote in their masterpieces, but not that dumb so while p.v. is actually a bit spread because anyway lower enough the electricity cost to pay back EVs/domestic batteries are not because simply they do not pay back despite the claim. And that's why we have blackouts and sky-high energy costs plus menace of scarcity of diesel and gasoline to makes EVs convenient "enough".
Charging at night is the logical choice FOR MOST, since normally we are active in the day and sleeping at night, but doing so means charging from the grid wanting a certain SOC in the morning. Green New Deal theorist have imagined remote workers who do not use their cars all days and workers how drive to the work and there charge the car in large parks with p.v. roofs. That's of course happen, but for a small cohort of people, while MOST EV owners so far are from dense cities where such model simply do not work because they have common garages, without p.v. or without enough p.v. both "at home" and "at work".
So far those theorist have found no solution: they can try push blackouts a bit more than natural to push people buying EVs as home batteries BUT due to EVs prices most people will not buy them anyway so the shift to renewables will not happen. They can't lower EV prices, most of the supply chain is in foreign hands and anyway there are way to expensive to manufacture to lower the price much. Not only, since they do not state clearly such cars-as-a-grid-balancers perhaps to avoid being accused of shifting costs to the people most EVs are NOT made to be used as home batteries. Something start happening BUT at very limited and slow rate. Some inverter-chargers charge on DC and so can offer "standard power" to the home, but most do not offer micro-grid islandic setups so they can't work in case of an outage, some V2L do exists with in-car inverters, but for very limited power (like 2kW while potentially the car can deliver 50+kW) etc.
That's the issue when managers are in charge: they dream something and run with the idea of fixing and detailing anything on the go, that the reality hit.