What large documents are you keeping in that binder? Your notebook can break, if one iPad isn’t charged I grab another one, we’ve been over this, okay the battery fails; again, it’s backed up. Maybe it can overheat in the sunlight (110°f haven’t had it happen), maybe you want to keep something extra private. I don’t really see the difference between changing writing tools in an app and in person tbh, but I’m pretty sure I can take an iPad almost anywhere. A tablet can do almost anything a notebook/binder can, the same is not true in reverse.