Not an advantage. Stop and go traffic means brake lights are constantly used. Also factor in use of headlights, heater, radio and electronics monitoring devices and you have a big drain on power for very few miles of forward motion. My daughter has a hybrid Altima, and the regenerative brakes can be heard kicking in going down hills, so that restores some power, but not all that was used going uphill (basic physics). Regular hybrids are much better than the Volt (best use of gasoline-powered engines combined with electric motors).
I didn’t claim that whatever electrics there are on a car do not use energy. But these also use additonal power on gasoline engines (via the alternator - no ‘free lunch’ there either!).
The gasoline engine has a base line consumption at idle - which the electric motor does not. That’s all I’m saying.
For the record: I am no fan of either all-electric cars or hybrids, for a multitude of reasons (mostly because non of them appeal to me in any way whatsoever).