5.3f Empty notes are better than no notes at all
Empty notes aren't useless in a zettelkasten, and an empty note is better than no note on the subject. The note just existing proves an interest in the subject and can aid your thinking on it.
I would also argue that this is also the case for "ghost notes", ie notes that are linked to but do not yet exist.
Source: https://anthonyamar.fr/Ω+Fleeting+notes/202106122255+Empty+notes+are+better+than+no+notes+at+all
See: 5.3 main notes are where your thinking is stored long term for what to put in a note if you decide not to leave it empty
See: antilibrary for more on how things can be useful even if you don't use them
compare: 5.3f1 collector's fallacy states that collecting knowledge is not the same as having knowledge for the view that having a note isn't the same as having knowledge