Thank you for your comment, it's a great point, the suggestions won't be as good for narrow fields. Over time we believe we can make them good for all fields but at the moment it works less well for narrow fields.
Note though that even with poor suggestions there is still a large positive impact on memory from answering the questions, so it still works even for questions where the suggestions are not so good (its just not quite as efficient).
However, when you are learning a very narrow field of study, the app does not create great suggestions. A complicated example, but see the following:
"Choroidemia patients have a normal electroretinogram"
presents: MRI, Melee, Moon, DNA.
Of course, I don't expect it to come up with something amazing for something that GPT-3 or other language models aren't trained on.