Your paper planner won't inform you that your first hour is in another building tomorrow or that the teacher is ill (and yes, the schedules would change less than 12 hours in advance). It's hardly comparable.
As for this project, I'm not sure how wise it is to build something that relies on scraping some unknown third party website when it comes to school schedules. I'd risk it for my own schedule, but if your scraper makes a mistake you'll get your kid in trouble. Maybe the teacher will believe "it's because my parents made this scheduling contraption" as an excuse, but they'll only accept it once or twice if they do. If there's any app I'd completely unlock in parental controls, it's this one, because it only seems to do the bare minimum anyway.