This is almost certainly one of those things where the tech has moved on. It definitely used to use a fair bit of fuel to get started. Not so much anymore.

Probably also depends on where you are? I'd imagine colder climates need to keep the engine running.

Even way back when it used a lot of fuel to get started, it only took a few seconds of engine off the make up that fuel.

I've had cars need jumping from too many starts draining the battery, though. So, mayhap it was less the fuel and more the battery/starter?

Modern cars will disable stop/start if the battery is low. My car won't even use the start/stop feature if the HVAC is operating at a 100% of it's capacity.