The prompts in a Spaced repetition memory system are an unordered, unstructured set. Each prompt is intentionally quite fine-grained and atomic, since that’s what seems to work best for effective memorization. But this lack of structure creates a feeling of wandering through a forest, able to see only one leaf at a time.
In some domains, this type of atomization is appropriate. For instance, if you’re studying hiragana, or a large set of foreign-language vocabulary, the inter-prompt structure may not be terribly meaningful—you really do have a huge sack of atoms to memorize.
But in other domains—say, physics or math—the atoms only have meaning as part of a broader structure. When prompts in these domains work well, I suspect it’s because they’re hanging on some invisible, broader structure that’s already in the reviewer’s head.
This atomization is the primary reason that Spaced repetition memory prompts alone are a poor communications medium. It also limits their suitability for long-term personal notes: Existing spaced repetition systems discourage evergreen notes.