Well it did take it a bit longer to start when I left my Cruze at an airport for two weeks, battery was stone dead. Had to use the key to get in and when the alarm didn't go off, that was a sign of a problem. So had to wait for AAA to show up for a boost, and was a tense drive home. Needed gas, but cheated by not turning the engine off.
A good design is where you can take a lab type supply and slowly increase the voltage to the operating point, solid state tends to go crazy, transistors that should be off are on because there is insufficient voltage to turn them off. And they can even burn up.
Assuming if the battery voltage does get a little low, some circuits will go crazy discharging the battery at a much faster rate, so much for low voltage protection. A good power supply design for a 5 volt output can be as low as 6 volts, 9 volts is more the norm for circuits going crazy. And always hot for convenience never was a good idea. Remote entry and anti-thief is always drawing current, and using the BCM to control everything, can switch stuff on if that voltage gets low. Augmenting the discharge of the battery.
Is this too complicated? You are darn right if you think so. Too dang complicated, never was a problem before using a real ignition switch, only the head lamps were always hot, but also had a real switch if you were half awake to switch them off. Turn off the ignition switch, radio is still playing, but depends on a contact from one of the doors to trigger the BCM to switch it off.
Left vehicles at an airport for over six weeks and started right up, add this to the history books, ha, don't worry about parking fees, my company paid for this. But back then airport parking was either free or at most a buck a day, add this to your history books.
A 116 year old problem is carbon in the gas, top tier is BS, while double platinum spark plugs last a lot long, still get carbon build up on that center electrode insulator that shorts the spark back to ground. Still have to clean them every 15K miles, sign is taking one for two engine revolutions to start it. Time to clean the plugs, one reason why I love the Cruze, a fun job.
Ha, a 61 Plymouth Fury like this one that took over a half a day to replace those 8 spark plugs, couldn't reach them from the top nor the bottom, with a long wrench was a 32nd of a turn for each one.
Have a spark plug cleaner that blasts them with ground walnut shells, get rid of that carbon without any damage to the plug surfaces.
Still have problems.