That is a good point, while typical city driving doesn't have that much idle time and lights and such, there are situations, such as in long lines at drive-thru businesses, where people will have their brake lights on idling for as long as 20 minutes at a time, rather than killing the engine and pulling the parking brake. Of course, many times, with that much idling, they'd need to run the engine for accesories like air conditioner, or heating (I personally would rather park and wait inside an air-conditioned, or heated building rather than a drive-thru any day)

A belt-starter hybrid sytem could take over for climate control by adding a small extra A/C compressor like the Accord to maintain temp. Combine that with an electric heater (electric wires running through the heater core), and you could have heat or air conditioning without starting up the engine. That would be relevant if say, you were so unlucky as to get stuck in the middle of a closed freeway for 6 hours in the hot sun, or snowed in (depending on climate). Such a system could save double-digit dollars for just a single incident like that in a big V8 vehicle. Instad of neeing to run an engine and incur pumping losses just to get a few steady horsepower for accessories, with a high-voltage system, the engine could spin at the max load the battery could handle intermittently to top off the battery, then shut off, just like how an air compressor works to keep tank pressure topped off. If you add those 12vAC plugs, then this approach would work any time you needed sustained power in a remote location. Someone who needed to run lots of generator-hours could easily save hundreds a year, and spare their worksite/environment from a lot of nasty fumes.