Can’t it run restricted to a single application in kiosk mode? Unless the application itself provides distraction, what would be distracting?

Blue light changes the way you think. Makes it easier to focus on the thing emitting the light, than the rest of the room. Just having a screen, with perfectly locked down control, can distract.

The very light it emits, the liquid glass lensing animations, etc

Why do we even want to pay $500 per device for something that is easily replicated by a $1 paper notebook? The only people that benefit from forcing classrooms to adopt these devices is big tech relying on corporate welfare to juice their books.

It's just not as good as a notebook. I've tried to make it as good. It sleeps, there's too much fumbling around with it to get to what you want. You lose the muscle memory of where something is in the book, you can't quickly flip to anything. You notice you used to do certain things, like flip to two different pages at once. Everything is just immediate and tactile.