Have you ever been in a situation where you forget to turn off your computer and your computer ended up overheated or any other related issues that may harm your computer (like you're running windows update on power supply without the battery and suddenly there's a power failure....?)
As for me, I always forgot to shutdown the computer at night. Mostly because I fell asleep watching movie on bed. And, usually I run my computer on power supply instead of using the battery so there were several times where the power outage occurred and my computer is still running. This is bad for any computers. So, one of the way to prevent that is by scheduling an automatic shutdown to turn off the computer at certain time.