My daily driver shuts off the engine at 70mph when I'm taking a highway off-ramp. Couldn't tell you how fast the turbo is spinning at that point, but there's less than 10 seconds between taking my foot off the gas at 85mph and the ECU killing the engine. 120,000 miles and the turbo's still fine, probably a more extreme example than what most cars would see.
If you're parking on level ground or even relatively level, there's zero need to use the parking brake. If I park on a hill, yes, I'll set it. My first few cars were manuals and my parents, being from the UK, always set the parking brake and I was taught to as well. Of course, every time I took it to a shop for something, whoever drove it would always put it in 1st gear instead of using the parking brake. This was before clutch interlocks were common too, so countless times I'd start it and it would lunge forward !
Have you tried it without shutting everything off ? I can't remember a car that doesn't have a "delay" relay - it kills pretty much everything for the instance it needs to supply 100% juice to the battery. Turn on the headlights and start a car. The lights on old cars would slowly dim while you cranked but on modern cars, they are shut off hard. Others have addressed things like the AC compressor. The blower motor will ramp up too, not instantaneously go full-blast.
