Glad to have scientific results on this, though in my view you could get this from first principles. Homework is onerous but it forces you to learn the material and get it into a configuration that works in your head, which you then validate with the exam.
as a fun aside here from the abstract it does come down to how you use it:
> AI users who maintain similar homework completion time as non-AI users experience small learning losses.
If the pure completion time of homework goes drops significantly with an LLM tool, I suspect these students are spending the extra time turning the material over in different ways to internalize, which is interesting.