How long does grocery shopping take you? I can do it in under 30 minutes, definitely under an hour. And in that half hour, my car charges… about three miles (@ 3.6kW)? That’s about how far the trip to the grocery store is. 50A 240V (10.8kW) only gets me up to 7.5 miles of charge in a grocery shopping trip.
Thats... extremely pessimistic. I have a VW eGolf, with our 7.6kW home charger it can go from empty - full in 4 hours. It has a 36kWhr battery w/ a range of 150 miles, so in 30 minutes that's on average a little under 19 miles (probably more because you get faster charging at first and slower when closer to full).
But more to the point, how many people have a regular commute, only have street parking at home, and ALSO couldn't be expected to have their employer provide charging at work? Are they doing on-street parking at work as well?
I know a lot of folks in the city who own a car but use it for errands and trips but not commuting. They're the people best served by slower charging at grocery stores, movie theaters, etc. 20 miles isn't a lot but if you're topping up every-time you use the car anyways it adds up or at the least means you only need to use the fast charger once every few months at the most.