And I'll also add that night-charging can only scale up to a point, there's a point where the country would end up consuming more at night than during the day.
So it really depends on the local situation, local energy mix, local infrastructure.
Charging at a couple of kW for the night is enough for almost everybody. Very few people drive hundreds of kilometers every day and the typical EV needs 10-20kWh/100km. The grid should handle that without a problem in most places, I think. Cars are parked most of the day. If most of the parking spots offer a kW or two charging becomes a nonissue.
So it really depends on the local situation, local energy mix, local infrastructure.