Certain systems on a vehicle make sense to power off. Do you really need the unit controlling your backup camera to be booted into standby while the car is turned off?
No, but I'm not taking thousands of six-inch family vacations per day, I'd walk if I wanted to travel a distance for which two milliseconds was noticeable.
I think you're mixing (bad) analogies to make some type of point but I'm not sure what it is.
The original comment you replied to mentioned cars in the context of booting devices often, so I simply pointed out that yes, actually it makes sense to boot up some devices when they go to receive input and not to leave them in standby as you suggested. In a vehicle that may sit off/idle for several weeks, it's best not to drain the battery unnecessarily.
