Besides memorization, § Spaced Repetition algorithms can be used to space out reviews of anything.
Ways this can be used with notes and Zettelkasten:
storing most of Zettelkasten in memory
use method similar to Incremental Reading:
Spaced repetition to review Zettels to see if you more or less remember their ideas (no flashcards yet)
This will schedule to review zettels more or less often
If you completely forget Zettel, create flashcards for it
is this desirable?
review notes to see if you have anything useful to add
it might be good to review only a subset of notes