Honestly whether or not this was effective seems less important to me than the adoption numbers.

Text book reading in this course was 10-15% at baseline ... but this AI thing got 90% voluntary usage ungraded.

Even if its worse per-hour than a textbook, you're now teaching 6x as many students _something_ instead of teaching a small minority everything.

So really it just becomes an optimization problem at that point because most students are at least in the funnel/in the running to learn something.

The paper kind of proves this itself ... they tweaked the quize formats mid-semester and where able to iterate which you can't do on a textbook that nobody opens in the first place

I'd argue the results are even better: just reading a textbook doesn't really teach you much. You have to do exercises, but they're expensive to create and grade. LLMs with a proper harness (see paper) tackle both.