Random notes create some mess in my slip-box. (e.g., my weight log, cat info). They do not contribute to developing ideas (Zettelkasten is about developing ideas, not collecting them).
I can treat them as a separate project (similar to Separate permanent notes and project notes) so they do not mess with the permanent notes.
In that sense, my life is an ultimate project, and life notes are not useful after the project ends.