In fairness, I didn't know crontab had @reboot. However, I wonder if it can distinguish between a real reboot and the cron daemon simply getting restarted. Probably doesn't matter... just a thought.
What if you want to stop your autorunning script after your Raspberry Pi has booted? If your script has already completed running, it will be gone from memory but if it’s designed to do something continuously, you’ll need to search for and kill the task.